You should have 6 ADF files, set install31.adf as DFO drive and boot up UAE, your hardfile should say something like DH0:
?, format it then give it a name (workbench etc).
When format is finished open install disk (DF0) install workbench using the installer, pause UAE and give DF1: - DF3, Extras31, storage31,fonts31.
Reboot then enjoy AOS :-) .