ES Events - Adding Custom HTML front-end

I'm trying to work with the custom field called 'Custom HTML'

It doesn't seem to be doing what I'd expect. Maybe I'm misunderstanding what it does... if so, maybe there's another way to do what I want...

OBJECTIVE: Have a custom field in the event category that allows the event creator to add some custom HTML to display in his / her event info page. (I use bootstrap button code to insert a few button links depending on what type of event it is)

PROBLEM: When I'm setting thing up back-end, I add the Custom HTML field to my Event Category but it forces me as admin to enter the HTML value there and then and it's fixed in the front-end display and the same for each and every event created in that category.

Hmmmm....

So if how it currently works is what is intended, I'm looking for another way to get custom HTML on my events. Worst-case scenario I'll set up modules for each and every event..... If I have to do that, are there inbuilt module positions in the event detail page?