The normal BookNow Software configuration should be followed, and the user should have both a GTM and GA4 account.
Below is the GTM container that can be used to import into the customer’s GTM account
BookNow_Software_GTM_Container.json
Go to GTM > Admin > Import Container > Select File > Existing Workspace > Merge > Overwrite Conflicting
Now go to ‘Workspace’, then ‘Tags’ and select ‘GTM to GA4 Connection’, click on ‘Tag Configuration’ and change ‘Tag ID’ to the customer’s GA4 Property ID, and close. Next, go to ‘BookNow Send Event to GA4’, click ‘Tag Configuration’ and ensure the ‘Measurement ID is the same as above.
Ensure the changes are published.
As BookNow Software is hosted on it’s own URL, customers must enable cross domain tracking to ensure user sessions are tracked correctly. Below is a document from Google on setting that up. https://support.google.com/analytics/answer/10071811?hl=en
Agency guide to setting up GTM on BookNow: