You can click the help button in the program and see the manual or parts of it - but I don't know if they have them online to download - Photoshop is weird that way
to do what you want to do - read Tutorials on Layering and Transparant gifs - I'll send you some links - can you pm me your email addy - I have some directions in a word document
edited - heres a good starter link -
http://www.myjanee.com/tuts/start/start.htm