[feature] docs - getting started abundant of conanfile.txt but no conanfile.py

Its probably me being unable to search properly, however I am unable to find any complete guides for new starters that show how to use `conanfile.py` rather than `conanfile.txt`.

What I would like to see:
An example of minimalistic project that uses cmake, whether to use package step and manually do `self.copy` what is the guide there?

Reasoning:
Just now I wanted to create a simple test project for showcasing RPATHs, but I failed to do that from memory, I had to log onto my work laptop and actually peek at the recipes there to know what I need to do in order to get it working.

There is this: that does not mention conanfile.py at all.

Then there are guides like this: Which is sort of incomplete - it doesnt provide a minimalistic example of `CMakeLists.txt` that conforms to that conanfile.py, it invokes `cmake.install` but there is no example of `CMakeLists.txt` that conforms to conan way of installing package, hence today after using conan for like a year+ I am wondering if i were creating my CMakes wrong, like maybe I should be invoking `cmake install` so I avoid issue like these: ?