I got ClassicWB installed on almost all of my Amigas (see my signature), by following instructions I was able to install it w/o a hitch.
You have A1200, that's the easiest one of all to install anything using PCMCIA-CF adapters.
You did not say what do you want to do with your Amiga, is it games, music, graphics?
Actually, you don't need to install any of the WB packs to get stuff working, just install programs you need and be done with it. The time will come when you are more comfortable with the OS and start to customize it.
Good luck.
