Good evening and welcome to the Events Calendar Support forum!
Thank you for reaching out to us.
I would love to help you with this topic.
As a first troubleshooting step, could you please provide us with your complete system information in a private reply using the instructions found in the following link?
https://theeventscalendar.com/knowledgebase/sharing-sys-info/
The first thing I would recommend is to read and follow these instructions: https://theeventscalendar.com/knowledgebase/new-user-primer-event-tickets/
As you can tell, you need to make sure to download both Event Tickets and Event Tickets Plus and install them on your website to get started.
Let me know how that goes.
Best regards,
Geoff B.