The main elements in a falafel recipe are ground chickpeas, also known as garbanzo beans, a lot of garlic, onion, spices such as cumin, and a bit of flour. You can top it with a yogurt and cucumber sauce as well.
Felafel is basically a deep fried veggie meatball, usually made with fava beans and/or chickpeas and when not most often bean based. Mash your choice of cooked, cooled beans with sesame paste (tahini) and spices -- onion, pepper, cilantro, garlic, I use a premixed "meatloaf seasoning". Add baking powder. Roll into balls and deepfry.