For Catalina, there are 6.20 pre-release binaries available. They will install ROOT under /Applications/root-$version. If you can use pre-built binaries, that might be the easiest way to get going.
For Catalina, there are 6.20 pre-release binaries available. They will install ROOT under /Applications/root-$version. If you can use pre-built binaries, that might be the easiest way to get going.