Clive Walker Registered Developer

This is an old post now but it might give you some pointers https://www.cvwdesign.com/blog/working-with-perch-categories

Good that you found a solution but a word of caution .... PHP 7.3 is end of life now. See https://www.php.net/supported-versions.php

The Bookings information should be here but isn't https://docs.grabaperch.com/addons/events/bookings/

You will need to contact the Perch team via the Chat window in your Perch account. They don't reply on here.