Hi Sven!
Thanks for getting in touch with us!
If you already have Event Tickets Plus installed and activated, the Attendees information options should show up automatically.
Could you please make sure you have Event Tickets Plus activated?
Also, please make sure you are using the latest versions of our plugins. Remember you can always download our plugins from your downloads page > https://theeventscalendar.com/my-account/downloads/
When coming back, please share with us your system information by following this guide > https://theeventscalendar.com/knowledgebase/sharing-sys-info/. We’ll see if there is anything strange that would indicate an error from there.
Let us know how that goes.
Thanks,
Victor