I don’t know if you managed to do it yet, but in that case it’s for future people finding this: I think you’re suffering from first-time-on-GitHub-itis. Don’t worry, I had it too, back in the day. I think that you might just have downloaded the source code of this program (at the top right it says download to zip). You can’t run that without compiling it into an executable (program) yourself. What you should do instead, is find the tab labelled “Releases” and download the release for your operating system (windows, macOS or Linux). That should allow you to run the program. :)