It's not too hard to do. I think there's 8 bolts on the back of the engine for the manifold. I'd pick up a Haynes manual though for the correct tightening order for putting it back together. Throttle body has to come off. Can't really remember now...just see what's in the way when you get to it.
first what engine are you talking about? if its an lx its pretty self explanatory throtle body does not have to come off. there are alot of diff things that can change things like egr etc. let us know all the info you can on your engine so we can help you better. help us help you.