The text you are quoting is on a page not written by us “how to install GVerb in Audacity”. Is it GVerb or Freeverb you want?
See here to get GVerb https://forum.audacityteam.org/t/cant-find-hard-limiter-effect/28776/2 .
The next 2.0.4 Audacity will have a new Reverb based on the original Freeverb. This is much nicer than GVerb. If you want to try that now, get the build at the top of this page http://www.audacity.homerow.net/index.php?dir=mac/&sort=date&order=desc .
Gale