Hello Colm,
Thanks for using our plugins and for reaching out! That’s a great question you have there.
As per our policy we are limited in supporting customizations, but I can give you some ideas to get you started on this:
The easiest might be adding a notice to the top and / or bottom of the submission form and draw the attention of users that they need to fill out PayPal data. You can do this under Events > Settings > Display tab > Advanced Template Settings section.
The other would be creating a snippet in your functions.php then checks when an event is being created and then doing a redirect to the appropriate page. This function might be of help: https://theeventscalendar.com/function/tribe_community_events_is_community_event/
And in general, you can find more functions here:
https://theeventscalendar.com/functions/
I hope this helps. Let me know.
Cheers,
Andras