Also, what's the difference between silken tofu, firm tofu, and extra firm tofu?
Silken - outside of the tub it comes in it has no body. It's basically slop haha. I use it for scrambled tofu and in cannelloni. You can use it for cooking desserts too - like mousse.
Firm - well, it's firm. You can slice and cube it. I use this in stir fry, and to grill slices for sandwiches.
Extra Firm - can't say I've ever had it but I would assume it's just harder than firm tofu.
And draining it, why do you have to do that? Do you have to drain it every time you cook it? What's it like if you don't drain it?
Tofu is kept in a water like substance to keep it moist no doubt. You only really need to drain silken tofu. If you don't you will get all the water in your dish and well that's not really nice.
Firm tofu is kept in very minimal water so you don't really need to drain it, just kinda dry it.
Hope that helps a little