Follow these steps:
Copy your ProveSource code from the Install page -> HTML Code.
On your Go High Level account, go to Funnels and select the Funnel you'd like to add ProveSource to.
If you want to add ProveSource to all pages:
Go to Settings -> Head tracking Code.
Paste your ProveSource code snippet.
Make sure you save and publish your changes.
If you want to add ProveSource to specific pages: