The Image Above is the sample going through G Clip with the default settings.
Step 1)You have to roll back the clip knob down until the horizontal lines are on the top of the peaks.Example below
Step 2) Now play the audio, while the audio is playing add gain
very slowly, Really use your ears and make sure NOT to add too much gain or the sound will start to distort.
That's it.
*Usually when you use Gclip on the Master Output, there's no need to roll back the clip knob.
I Hope this helps.