I’ve always installed it alongside the full version of XCode, but yeah, those instructions look fine, and as you should be able to see from the list of utilities the article lists, it includes make .
You run make against the makefile they give you on GitHub, alongside the source code, and that gives make the instructions to compile the source code into the executable you want. It really should be that straight forward.
Then copy the resulting application to wherever you want in your path (see details I shared with you earlier).
Hopefully you can follow that, if not, I would suggest maybe taking advantage of SUMMERFEST2020, and grabbing a copy of Joe Kissel’s Take Control of the Mac Command Line with Terminal and getting comfortable with the Mac command line. It’ll open up an entire UNIX-y world of automation for you.
Hope that helps.