Hi! Thanks for downloading the game!
Since I don’t know know how much experience you have with Amiga emulation, I’ll try to explain things in detail, I hope it doesn’t come across as patronizing.
The game and the assets are in the NEONnoir.lha file in the downloads page. This is like a zip file that was popular on Amiga.
In FS-UAE, you’ll need to set up Amiga 1200 emulation. If this is your first time, I would recommend checking out https://www.youtube.com/watch?v=fq7VUxVKwcA, he uses a Linux system, but it should be the same for Mac. Basically, you’ll be getting the Amiga ROMs, creating a virtual hard drive, installing the Amiga operating system on it, and you should have a working Amiga. Unfortunately this process take a while to do it it’s your first time. However, you’ll only have to do this once, ever.
Once you have a working Amiga system in FS-UAE, you’ll need to copy the NEONnoir.lha file onto a virtual hard drive. You’ll then need to unpack the game using the lha tool at the command line (inside the Amiga emulator, not on your Mac’s command line) like this “lha x NEONnoir.lha”
Doing that will create a new directory called NEONnoir and it it is the game, double-click it and it should run.
Oh, and you’ll need to make sure you’re emulating an Amiga 1200.
I hope this helps.