WHDLoad is compatible with OS3.9 and 3.1. So there's no problem in that regard.
You use WHDLoad by installing it. Then you need install files for each game you want to install. These install files need the original floppies of the game you're trying to install. Some websites offer pre-installed WHDLoad games; then you don't need the floppies and install file.
Get the latest WHDLoad version and install files from
www.whdload.de
