What you need to do, and what that thread covers, is edit your sudoers file to allow your user account to sudo those commands without you having to type a password. You do the editing by running the visudo, see this post for how to do that.
You want to be as specific as possible to prevent unwanted commands being executed without authorisation. In this case you'd add the lines
your_short_username ALL= NOPASSWD: /usr/bin/chown -R Mac:staff /Library/Audio/Plug-Ins, !/usr/bin/chown -R Mac:staff /Library/Audio/Plug-Ins *
your_short_username ALL= NOPASSWD: /usr/bin/chmod -R 755 /Library/Audio/Plug-Ins, !/usr/bin/chmod -R 755 /Library/Audio/Plug-Ins *
...substituting your short username for your_short_username in both lines.