This version of MicroMoth is compatible with Lua 5.x and PICO-8 Lua.
Dowloading a single file is all that is needed, so the word 'installation' is perhaps overkill. All you need to do is take the MicroMoth.lua file, and place somewhere that it can be found when importing.
If using the PICO-8, you will also need the contents of math.p8. This provides a minimal math table required by MicroMoth.
An example of MicroMoth Lua in use can be seen in main.lua.