I want to mod Witcher 3 GOTY and have been told "You need GOTY version 1.31" and to do this "Open GOG Galaxy client and go to your Witcher 3 GOTY pane. Click on settings button (icon with two short lines with dots on top) ==> Manage Installation ==> Configure ==> Unckeck autoupdates and choose the 1.31(A) game version "

I'm a complete noob and can't seem to find this. Can anyone help? thanks