Sara Greene and her husband are hosting a Passover Seder for the first time at their home in Cambridge next month.

She is writing her dissertation, he is a medical resident, they are the parents of a 7-month-old infant, and the holiday begins on a weeknight. When she saw the link on a friend’s Facebook page, she did not hesitate: She ordered a “Seder in a Box.’’

“We’re having all these people over, and I haven’t done it before,’’ she said. “The Seder plate has a lot of things on it. You just have to kind of remember to get all the different aspects of it.’’

Hoping to make Passover more accessible to the younger set, JewishBoston.com is offering its first do-it-yourself Seder kit. Free to Boston-area residents, ages 18 to 40, who sign up by April 8, “Seder in a Box’’ includes just about everything but the food and the guests: a Seder plate, a basic Haggadah, a leader’s guide, recipes, a shopping list, instructions for setting the table, and a matzo cover. Oh, and some green plastic frogs, representing one of the 10 plagues.

“We wanted to take the guesswork out of it for people who have never done it before,’’ said David Levy, the editor of an online hub for the area’s Jewish community, JewishBoston.com.

At first, Levy said the website’s advisory board of people in their 20s and 30s debated whether to host a big Seder for their peers in the Boston area. They wound up deciding it would be better to help people learn to do it themselves.

“There’s not the pressure of what someone else thinks a Passover Seder should be,’’ Levy said.

Barry Shrage — president of Combined Jewish Philanthropies, which established JewishBoston.com last year — said the “Seder in a Box’’ is one way the organization is trying to reach out to the next generation of Jewish families.

“If you look at what’s happening out there, 50 percent of Jewish households are now interfaith households,’’ Shrage said. “There’s a spark of interest in Jewish life among people who would have never even thought about it before. We want to be right there and help make it available for people who want to try to engage in Jewish life.’’

Seders are ceremonial meals typically held on the first two nights of Passover, an eight-day holiday that begins at sundown April 18 this year and commemorates the Jews’ liberation from slavery in ancient Egypt. Friends and family retell the story of the exodus, reading from the Haggadah, a religious text that sets the order of the ritual. The service usually involves praying, singing, reflecting, and eating foods that symbolize aspects of the Passover story. Bread and other foods with leavening are replaced by matzo, symbolizing the haste with which the Jews left Egypt, leaving no time for bread to rise.

“For people who haven’t had one before, who are just out of college or moved here and don’t go home anymore, [Seders] can be a little daunting on every single level,’’ said Patty Jacobson, director of JewishBoston.com. “What sort of Haggadah would I use? . . . How do you set the table? What goes on a Seder plate? What kind of wine should you get?’’

“The Wandering Is Over Haggadah’’ included in the kit was written by Levy in simple, conversational English with a sprinkling of Hebrew. It is also short, but easily added to or modified.

“We recognize that Seders can go on for hours and hours,’’ he said. “That’s an option, but if you want to do a half-hour Seder that is meaningful, you can.’’

The idea is not entirely original. Hillel groups and other Jewish organizations have tried similar programs, and a California man registered “Seder in a Box’’ as a trademark last year; his plan was to sell packages that included a how-to DVD, prayer books, and traditional foods, according to the US Patent and Trademark Office website.

JewishBoston.com “adapted the concept for the Boston market,’’ Jacobson said.

Rabbi Michele Lenke of Temple Beth Shalom in Needham said she had someone in her office the other day who had never hosted a Seder and was fretting about how to do it properly, even wishing aloud that they could run a video that would walk them through each step.

“People have so many memories of different Seders, and I think they so desperately want to do it right,’’ she said.

She called “Seder in a Box’’ a great idea. “It’s providing an entrée,’’ she said. “It’s opening a door.’’

Lisa Wangsness can be reached at lwangsness@globe.com.

© Copyright 2011 Globe Newspaper Company.