We would really need to know more about your setup.. I assume you don't work on TicketMaster, but rather send people to TicketMaster to handle your payments?
Once off your site, you can't add your analytics to another site... but there is likely information passed back to your site from TicketMaster...
However, the first thing you need to do is talk with your developers.. what information do they get back and can make available to you for tracking.
If you have never done product / purchase tracking in Adobe, you should read this first:
https://experienceleague.adobe.com/docs/analytics/implementation/vars/page-vars/products.html?lang=e...
