Hello again Dirk,
You are correct, the 2 files mentioned are the ones you need to modify AND they both are made out of HTML code (wrapped in a PHP file – so no actual PHP knowledge is required).
Basically you need to tweak those two files to your liking and save them back in your child theme’s /tribe-events/ folder under the correct path.
You might want to read our Themer’s guide to get a sense of how that works.
To customize HTML code, you could totally use something like an online editor (e.g.: https://codebeautify.org/htmlviewer/)
Just to set expectations, the scope of our support is mostly to get our customers started on the right track and to help them in case of issues.
We unfortunately do not provide complete support for customization.
As per your last question, our users usually do not share their customizations with us alas.
If coding is not really your cup of tea, you could always hire one of our recommended customizers to do the customization for you.
I wish I had a better answer for you, but for now it’s the best one I have unfortunately.
Have a good weekend,
Geoff B.