LAS VEGAS – On July 6, the first day of the MGM Resorts Summer League in Las Vegas, Celtics.com was granted unprecedented access to the Boston Celtics coaching staff.

There was nothing we weren’t present to observe as the team prepared to take on the Philadelphia 76ers at 4:30 p.m. local time that evening, beginning with the coaching staff’s meeting in the morning, and concluding with the postgame address in the locker room from acting head coach Jay Larranaga.

What follows is a diary of the day’s events, and in turn, the closest public view of how the Boston Celtics prepare for a game. This is a look behind the green curtain of a Celtics game day.

10:25 a.m. PT: A group of coaches steps off the elevator on floor 51 for their 10:30 a.m. meeting, set to take place in suite No. 5106 at the team hotel. But they don’t know how to find the room, because the sign indicating the direction of room numbers doesn’t include a 5106. No one knows where to go, until a hotel employee walks past and explains that in order to find the suites, the group must head down the hallway to the right and through the closed black doors. A member of the group quips, “That’s misleading,” to the laughter of everyone else.

10:27 a.m. PT: Staff members enter the suite, where 14 red chairs are set up in two rows in the middle of the main living room, which has a separate bedroom off of the right side. The chairs face a large TV screen in the front-center of the room. Lounge chairs and couches dot the perimeter of the room, after they were moved to the edges to create space for the 14 chairs. On one of those couches sits head coach Brad Stevens. Sixteen people, not including Celtics.com, are in the room; a group that features coaches, members from the security and public relations teams, and a couple of the coaches’ children.

10:36 a.m. PT: Stevens opens the meeting with a few quick notes. He tells the staff that if they have any of their position players coming into town – “I know Terry (Rozier) and Jaylen (Brown) are two,” he says – the team has a gym available for them to use for workouts. “Individual gym time is tremendous,” he says. The catch is that in order to use the gym, they must reserve the time for the workout a day ahead. He adds that Kyrie Irving may stop into town, and that if no players use the gym, he may book it for the staff’s kids.

10:40 a.m. PT: Stevens exits the room and relinquishes the reins to Larranaga. Larranaga reveals the starting lineup he’s going to use for the game – Pierria Henry, Jabari Bird, Justin Bibbs, Semi Ojeleye and Guerschon Yabusele.

10:42 a.m. PT: Robert Williams, Boston’s first-round pick this season, walks into the room – 18 minutes before the players’ 11 a.m. meeting was set to begin. Larranaga smiles and says, “Hey, can you give us a few?” Williams obliges and heads back to the hallway.

10:43 a.m. PT: Larranaga returns to scouting Philly. He concentrates on transition defense, pick-and-roll defense, and body position. He tells his staff, “Let’s hit the players with as many little pieces of our philosophy and culture as possible each day.”

10:45 a.m. PT: Larranaga moves on to offense and says the C’s need to be slower with the ball and faster without the ball in transition. He shows a clip of LeBron James from the Playoffs allowing a sprinting Tristan Thompson to catch up and get into the play, which leads to an alley-oop layup. “Not a big difference,” Larranaga says of James’ speed, “but a great impact.”

10:52 a.m. PT: The coaches’ meeting ends and they wait for the players to arrive for the 11 a.m. meeting. In the meantime, a few people in the room discuss how a piece of avocado toast costs $12 downstairs.

10:57 a.m. PT: The players walk into the meeting room and fill 13 of the 14 open chairs. Jamie Young fills the 14th.

11:03 a.m. PT: Larranaga heads to the front of the room and immediately begins talking about the family atmosphere the Celtics seek to promote. He says family members are always invited to join the team on the road. “Even though it’s professional, this is a family atmosphere,” he says.

11:06 a.m. PT: The film turns on and Larranaga immediately dives into Boston’s defensive principles. He tells the players to be long and to shrink the floor. He says Aron Baynes was the best defender in the league last season in terms of points allowed per possession in large part because he always played with length.

11:09 a.m. PT: Larranaga moves on to the clip of the James play in transition. He highlights Thompson’s effort by saying, “Everyone must sprint if we’re asking that of the ball handler.” Then he comments on James’ pace in transition: “I think that’s the difference – just a little more patience with the ball.”

11:16 a.m. PT: Larranaga asks the players if they know what “mucking it up” means. None of the players, other than the Celtics vets, know what it means. “Mucking means you’re back off of your man and long, to help around the basket when your man can’t shoot,” says Larranaga. Again, he makes reference to Baynes.

11:20 a.m. PT: One final lesson on defensive principles is relayed as the film session ends: “The basket is most important, then the ball, then shooters,” says Larranaga.

11:22 a.m. PT: The players stand up and all of the chairs are moved to the edges of the room, revealing the outline of a court’s lane that was previously taped to the floor. The team now uses the meeting room for an informal walk-through session.

11:24 a.m. PT: Assistant coach Jamie Young begins to lead the first portion of the walk-through, which is defensive-minded. He casually calls out the starters’ names– the first time players are notified of who’s starting – for them to step in and set up a defense, and then asks five other players to step in to run scout offense. A basketball is given to the offense.

Larranaga chimes in before the walk-through begins. “I understand you’re in sandals, but if KG (Kevin Garnett) was in this room he’d be in his stance, yelling out coverages, with long arms, just like he would in a game. Use these 10 minutes to get better. If that’s what he did, that’s what we should do.”

11:26 a.m. PT: Young and the coaching staff walk the team through the defensive game plan for Philly. They single out a couple of Philadelphia’s top players, then they walk the players through defensive calls and correct positioning. These are true teaching moments. They stop the players in their tracks and correct any mistakes that are made. “Don’t skip steps,” Young tells the team.

One defensive switch doesn’t operate as it’s supposed to, as Bibbs, who was being screened, called for the switch. Larranaga stops the players. “We can’t let the guy on the ball do it,” he says of the switch call. “The screener’s man must make the call.”

11:40 a.m. PT: The walk-through switches to offense, with the starters first running through plays. Henry takes control of the ball at the imaginary top of the key, and he begins calling out plays: “1,” “1-snap,” “Swing,” “Swing-go,” and so-on. The coaches say they want every player to get at least one rep of each play call.

11:46 a.m. PT: The walk-through ends, and the players are put through five minutes of stretching with the strength and conditioning team. They’re notified that the bus will depart for the game at 3:15 p.m.

3:08 p.m. PT: Players begin trickling onto the bus, where Larranaga is sitting in the front-right seat with his son by his side. Larranaga stops a couple of players as they walk onto the bus to give them last-minute coaching notes.

3:15 p.m. PT: The bus departs for the arena.

3:32 p.m. PT: The bus arrives at the Thomas & Mack Center.

4:10 p.m. PT: After being confined to watching film in the locker room while the game before theirs unfolded, it’s just about time for the team to take the court. Larranaga steps to the front of the room and delivers three keys for the game: “First: Sprint back in transition. Be long. Look like a team. No. 2: Communicate coverages. The best defenses have talkative 4s behind the action. Third: Be great in pick-and-rolls.”

Larranaga then comments on the offense: “Keep the basket clear. When you get the ball, see if you’re at an advantage or not.”

Lastly, Larranaga offers a note of encouragement: “Have fun. Be a part of our organization to the best of your ability. Do the things that we know lead to success. Be the best team in this league at watching tendencies.”

4:24 p.m. PT: After reviewing more film as a team, the players stand up from their chairs and walk to the center of the room, with Larranaga standing in the middle of them all. He looks the players in their eyes and delivers a message: “I made a mistake earlier this week. I told you to break our huddles with ‘together.’ We’re a family…

“… Feel like a family. Play like a family. Family on three…”

The team joins in unison: “One, two, three – FAMILY!” and they take the court.

4:35 p.m. PT: The opening tip is tossed and the Summer Celtics begin play in Las Vegas.

5:02 p.m. PT: Semi Ojeleye scores a basket, and for the second straight year, UNLV’s PA announcer, Dick Calvert, struggles mightily to pronounce his name: “That basket scored by Semi Oh-lay-joe-lay,” he says, to the amusement of Boston’s bench and the onlooking crowd.

5:36 p.m. PT: Boston takes a 48-45 lead into halftime. Ojeleye has already logged 13 points.

5:39 p.m. PT: The Celtics briefly meet in the locker room at halftime, which is only an eight-minute break. They talk almost exclusively about defense, but before they know it, it’s time to head back to the court.

5:44 p.m. PT: The second half begins.

5:49 p.m. PT: The Celtics announce that Rob Williams will miss the remainder of the game with a left-knee contusion.

6:26 p.m. PT: Hassan Martin scores an and-one, tip-in layup with 1:50 left in the game. His free throw gives Boston an 88-87 lead.

6:28 p.m. PT: Guerschon Yabusele scores the game’s next five points, off of a driving dunk and a 3-pointer, to seal Boston’s win.

6:33 p.m. PT: The Celtics finish off a 95-89 win despite Furkan Korkmaz scoring 40 points for Philly. They shake hands with the 76ers, then head back to the locker room.

6:39 p.m. PT: An excited group of Celtics celebrate their win before Larranaga steps to the front-center of the room to address them. He begins with coaching lessons. He tells the players that they cannot become frustrated by their missed shots, and adds, “The mistakes that each one of you made in the game, work with your assistants and let’s make sure we don’t make them again tomorrow.”

Every player nods his head in acknowledgement.

6:41 p.m. PT: Larranaga has completed the teaching portion of his postgame speech. Now it’s time for the fun part.

He singles out Hassan Martin as an example of true professionalism. Martin, who did not play at all during the first three quarters of the game, played the final 5:15 of the contest and tallied eight points and two rebounds during that stretch, including arguably the biggest bucket of the game, his and-one putback that gave Boston a lead with 1:50 remaining. Martin’s ability to perform when his name was called is what the NBA is all about.

“Always stay ready,” Larranaga says passionately. He continues, borderline yelling with excitement. “Hassan goes in, and he’s READY! That’s being a pro!”

Excitement brews in the room, as everyone stands and begins clapping and yelling toward Martin to congratulate him on his efforts.

6:43 p.m. PT: The team huddles up in the center of the locker room as each player piles his hand on top of another toward the center ceiling of the room.

“Family on three: one, two, three – FAMILY!”

6:46 p.m. PT: Larranaga heads out of the locker room to meet with the media, and is soon followed by Semi Ojeleye and Rob Williams. Each speak to the media for about five minutes.

7:08 p.m. PT: The team bus finally pulls out of the Thomas & Mack Center to head back to the team’s hotel. A day of basketball that began at 10:25 a.m. now concludes at nearly 7:15 p.m. – all just in time to begin preparing for the next day, during which the staff and the players will repeat the entire process with an added morning shootaround in at UNLV.