The following five grains and anything made from them are considered chametz: wheat, barley, spelt, rye and oats.
Kitniyot are legumes and also certain grains and seeds. These include: rice, corn, sunflower seeds, sesame seeds, soybeans, peas and lentils. The tradition is that these items are permitted to eat if one is Sephardic. Ashkenazi Jews refrain from eating them during Passover.
This seems like one would have a very restrictive diet during Pesach, doesn’t it? Once you get used to the prohibitions, you will find many recipes which fit nicely into the holiday. I admit that living in Israel makes it simple to keep the kosher laws for Passover. However, even here many people have daily meals of chicken, potatoes, carrots, etc.!
It might be a good idea to Google “passover recipes”. You will find lots of great options. Soon, I will give you some menu ideas and what we will be having at our seder.
Shalom! Shavuah Tov! (Have a good week!)