The first "leaves" that sprout are cotyledons. They break out of the seed, and look like ovals, or thin pringles (those chips). As soon as they break out, get them under a flourecent light, CFLS are good, or natural sunlight, otherwise they will get light deficiency, will stretch alot, and will be a really shitty plant. Usually if under light, after a day or two, you will see the first set of serrated edge leaves, that you can't mistake for anything other than pot. The first set will only be one leaf. Then so on.