Workbench floppies isn't a requirement to play most old A500 games.
And in this thread you'll find a list you might get working without even a kick.rom
http://eab.abime.net/showthread.php?s=&threadid=8264
Other than that, when you get winUAE you might want to read up on the FAQ in the game request area to find out where you can get games from.
And might want to read the manual for winUAE if you can't remember how the A500 or other machine was setup. The Back to the roots configurations were badly out of date with the current winUAE last I checked