Do I have to be a computer programmer to understand Xoops?

Not at all...but you need to be prepared to learn a bit along the way.
There will likely be times where you will need to learn a bit of html, php, etc. What will happen is you will come across references to these in the forums, in the instructions for installing modules, and in the files themselves if you look inside and see what is there.

At first, if you are a total non programmer who likes to see what you get rather than look at how it all works in the background kind of person like me, you will possibly be horrifed, or at least loose some confidence the first time you are asked to dig into a file and change the code to resolve an issue or set up a module, or theme.
However it isn't going to be as difficult is you say to yourself -it is ok - it is just like learning another language. Loads of people can read and speak more than one language...and learning to read and use html and php is pretty much the same.

I have found it ok at first to not have to understand what the code means or why I am putting it somewhere - I am happy if an intruction says 'paste this code here'. We can all do that! Copy and paste a bit of code and put it in the spot I am told. Easy Peasy! In time no Doubt I will begin to understand what it all means.

People learn in different ways...playing with xoops is a hands on learning experience - don't make it a text book one - it will get boring! Learn the laguage as you go.

This Q&A was found on XOOPS Web Application System : https://xoops.org/modules/smartfaq/faq.php?faqid=162