Those instructions are a beginners guide to git and compiling lol the clone repo thing means download all the files in the GitHub page then you navigate to the directory in terminal using cd then make sure any dependencies are installed so packages the program requires to be functional then you build it or compile it from the source code then install if no errors happened during the compile process most programs are already compiled and packaged in binaries such as deb packages rpms or exes you're just creating those through this process of compiling
the way i see it, if you don't have that figured out, you're a third-rate developer. valve did 100% of the legwork to make sure steam play works the way it does and now they sell hardware based around that ecosystem, you're either stupid or afraid of money to not support that.
i can't speak for other third-party anticheats but i'm so sick of hearing FUD about Battleye and EAC when they're bottom of the barrel process wardens that barely protect anything from cheats at all