I'm glad you found your way here... as the old maintainer of emulation.net, I'm glad you were able to find the new community
Unfortunately, MacScene had a meltdown last year, so the emulation stuff is a lot harder to find than it used to be.
The best solution for running OS 8.1 is Basilisk II: you'll need a Quadra ROM (from a Mac Quadra) in order to do it. After that, go to the emaculation website for the tips and tricks; you'll need the emulator binary and the front end binary. Set up your configuration in the front end, and set it to boot from either an 8.1 CD or a locked disk image (locking it is important). Use the front end to generate a blank disk image to install on to (or use disk tools or diskutil), and fire up the emulator. The rest should be self explanatory, except for getting ethernet emulation working, for which you'll need to work through the emaculation forums.