proper amp hook up?

I this my sound dumb, but pretty much coming from a newbie in the car audio world. I have an opportunity to get into a local stereo shop and I have done stereos and some amps, but when I do installs I'm with a friend and need usually does the amp hook-up and what not. I was wondering if someone can explain hooking up amps better to me. I don't quite understand how too hook up in different Ohm's and when to use series and parrell. So does any know how to explains this to me or have a link to diagrams to help me better understand it. Any tips my help. I really want this job and I don't want to screw up my chance, so any help is appreciated.

Thanks Alot,

Jason