In this regard, what food do I need for a Passover Seder?
There are at least five foods that go on the seder plate: shank bone (zeroa), egg (beitzah), bitter herbs (maror), vegetable (karpas) and a sweet paste called haroset. Many seder plates also have room for a sixth, hazeret (another form of the bitter herbs).
Then, what can I expect at a seder?
During the course of the Seder, the participants drink 4 glasses of wine (or grape juice), accompanied by prayers for each glass. There are no particular requirements as to what should be eaten during the main festive meal other than matzo and tastes of the foods represented on the Seder plate.
Why we need eggs at Passover. So it became customary in nearly all Jewish cultures that, at end of the Seder and before the parade of dinner food begins, hard-cooked eggs are eaten — dipped in salt water to remember the tears of the ancient Israelites and destruction of the Temple.