Washington (CNN) Over the past two months, since his buzzy launch February 1, Sen. Cory Booker's campaign has gone relatively quiet — methodically grinding away under the guiding philosophy: "You've got to organize, and get hot at the end."

"We're trying to win the election," Booker's campaign manager Addisu Demissie told reporters Thursday. "We're not trying to win a news cycle."

But that slow-and-steady pace now seems poised to pick up. Booker will step back into the spotlight Saturday in Newark, with his first major rally as a candidate. The event will kick off a two-week national tour for Booker, which in its first week will take him to Iowa, Georgia and Nevada. In his remarks, he will lay out his broad vision for the country, oriented around the theme of creating a more just society.

It also comes at a moment of trial, with Booker's momentum apparently stalling after a muted start.

In two polls released this week, by Monmouth University out of Iowa and St. Anselm College in New Hampshire, Booker's support registered in the low single-digits, lagging behind half a dozen other candidates.

Those numbers follow a middling first fundraising quarter for the New Jersey senator, who reported raising $5 million — enough to sustain a campaign operation, but far less than top fundraisers Bernie Sanders ($18.9 million) and Kamala Harris ($12 million), and even trailing newcomer Pete Buttigieg ($7 million).

Booker's campaign has attempted to downplay that gap: "The raw numbers of money is irrelevant," Demissie said Thursday. "It has to be connected to a strategy."

That strategy has been to build slowly, putting the pieces in place now, particularly on the ground in early primary states, to make the most of a breakthrough moment later on.

But Demissie acknowledges the need "to stay relevant in the conversation" in the meantime, amidst a competitive and increasingly crowded Democratic field — and so the campaign is beginning to ramp up its public exposure, beginning with the rally Saturday in Newark.

"Now, it's phase two," said Robert Wolf, an influential Democratic donor, who gave money to Booker and four other candidates in the first quarter: Harris, Buttigieg, Sen. Kirsten Gillibrand and former Rep. Beto O'Rourke.

At this juncture, Booker "needs to continue to creep up in the polls and really solidify himself in the top half dozen" candidates, Wolf added — and Booker's rally in Newark could mark a major moment in that effort.

"Everyone has one day to launch," said Wolf, "so it's an important day for him."

As with Harris' kickoff rally in Oakland and O'Rourke's in El Paso, Booker's event will be set in a place central to his biography: Newark, where Booker won a city council seat as a 29-year-old political upstart, beating a longtime incumbent, and then went on to challenge longtime incumbent Mayor Sharpe James.

In a Democratic field that could balloon into the twenties, Booker points to his political and governance education in Newark as his special sauce. In his narrow loss to James in 2002, Booker learned the art of political combat. And, after he came back to win the mayorship in 2006, he worked to transform the city as its chief executive.

On Saturday, Booker himself is not expected to focus on that piece of his biography. But his event, and a roster of other speakers, will help him do the talking. The kickoff rally will take place in downtown Military Park, a public space that underwent a dramatic makeover under Booker, nearby a Whole Foods that Booker helped bring to the city. On hand to introduce Booker will be his successor as mayor, Ras Baraka, as well as Sen. Bob Menendez and Gov. Phil Murphy, among others.

Booker's story has so far been eclipsed by those of other ascendant candidates, however — including another mayor, Pete Buttigieg of South Bend. Buttigieg benefits from a certain degree of novelty relative to Booker, who was in his own Wunderkind Mayor phase more than a decade ago.

Incidentally, Buttigieg will hold his own rally this weekend in South Bend, to officially announce his campaign for president after an exploratory phase. But Booker will be launching a new phase of sorts as well, beginning to hone his campaign narrative and home in on a central theme of justice.

Booker's organization was "very intentional in wanting to do this at this point in the campaign" as opposed to when Booker first jumped into the race in February, Demissie said, "...as a moment to be able to say clearly and above the din of what's happening on a daily basis, why Cory's in the race and what he's fighting for."

The campaign will expand its reach in the coming weeks, with plans for Booker to visit Georgia, California, Wisconsin, Texas and Florida for the first time as a candidate. And they will begin hiring in Super Tuesday primary states soon, campaign officials said Thursday, now that their teams on the ground in the first four primary states are up and running.

Booker is also making a turn toward a more pronounced policy focus. During a swing through New Hampshire last week, Booker tailored his stump speech to get more into the weeds of his "baby bonds" proposal, which would fund a savings account for every child in America until age 18, in an effort to diminish inequality.

"Not just sentiments," Booker told the crowd last week at Rev. Al Sharpton's National Action Network conference. "I'm fighting to deliver substance."

That appearance drew rave reviews for Booker, as did his remarks this week at the North American Building Trades Unions. His team hopes to continue racking up such momentum slowly and methodically, confident that the Democratic field remains wide open.

"They don't need a breakthrough moment at this point," said Mo Elleithee, executive director of Georgetown University's Institute of Politics, and a former Democratic operative. "They need an infrastructure — so that when he does have a breakthrough moment, he can capitalize on it and sustain it."

Plus, breakthrough moments — like bolts of political lightning — can be "fleeting," Elleithee added. "It's narrative that wins. That's what he needs to focus on, is getting his narrative out there."