Hi, Elaine!
Tempeh is a whole soy product, that is used in Indonesia a lot. It is cultured soybeans (a special mold is added to the beans, and it grows between them....sounds gross, but it's not. Kind of like cheese!). This culturing process makes the beans easier to digest, so some people who have difficulty with soy (gas!) may have an easier time with Tempeh. And the process also makes the protein more easily assmilated.
When I first started using Tempeh (1970's), I used to fry it in a pan, and it tasted like chicken/fish to me.
There are several books out with just recipes for tempeh, or you can look up some recipes on the internet.
After steamiing (unless it says it's precooked and ready to eat), you can grate or mash it and use it like I do in salads/spreads. You can blend it to make a base for dips. You can crumble it, with or without frying, to add to chili or other recipes instead of meat. You can bake or broil it.
You won't find it in most grocery stores (maybe in big cities?). If it's there, it would be in the natural foods or the international foods section, frozen or refrigerated.
I buy mine at health food stores. It's not very expensive at all.