customize user template

That's the file you'll need to edit, there is no other file. Any other changes would be core edits which I can't advise on. Review Joomla templates on how to load a module position; no idea if this will work in CB templates though.

There are several ways you can achieve multiple profiles. For example you could use a single-drop down field where different types are selectable. You'd then use incubator project CB Conditional to show/hide fields/tabs based off that fields value. Another option is to create multiple CB templates then use incubator project CB Template Changer to change to those templates (set to read only so user can't change it).

Unfortunatly giving up is not an option in my position : ).

I think I can solve this problem by adding html to a user profile template (i.e. luna)

but when I add any code I don't see anything. I hope the questions I'm going to ask are simple answers to somebody out there.

1 - what file in the luna template would I add the html to?

2 - to i need to have an active tab on a profile in order to see the user profiles (i.e. luna) and the html I have added.

3 - any other help youo can think of : )

Unfortunatly giving up is not an option in my position : ).

No one said anything about giving up please see my previous reply for several solutions.

1 - what file in the luna template would I add the html to?

It doesn't have one, it uses the Default templates PHP file.

2 - to i need to have an active tab on a profile in order to see the user profiles (i.e. luna) and the html I have added.

Don't understand the question.

3 - any other help youo can think of : )

See previous reply for several no-coding solutions.