Well, many of us work with ubuntu. One popular option is to use version 18.04, also called Bionic Beaver. Good choice! When it comes to development, python comes in picture. The default python version that is provided 3.6.9. Why not experiment a little bit with newer versions like 3.8.5, or the upcoming 3.9? One option
Doxygen is the de facto standard tool for generating documentation from annotated C++ sources, but it also supports other popular programming languages (we want Python as well). As in every other software tool, the best way to learn it is starting to use it in your everyday life. There are many examples and tutorials online.