Apart from the lack of a physical manual, you should be able to get hold of (the far better) AMOS Pro from
Back2Roots (assuming the download is still there, I'll check [ed: checked]).
The online manual is sufficient if you have half a clue, the forums discussed elsewhere here will help you get started.
Generally, AMOS is good to begin getting your head around the BASICs of game development, but I would recommend AmiBlitz (Blitz Basic) if you wish to do more solid Intuition development.
In the end, however, all roads lead to C, so, if you're feeling game, you might start there by downloading GCC and it's associated files from the 'gg' directory of Aminet and looking for some 'Kernal Manuals' on eBay (other people may give you less broad hints, but its only my lunch break and I don't have that much time :-P )
benJamin
"Spells like teen's on spirits."