That may be true, but learning begins with starting…
So, you should just start using Krita like Ahab suggested.
You will not learn how to master Krita by using MyPaint.
Start with simple things, don’t use 50 layers at the beginning, but start with one or two, use one of the two following ways whenever something is not clear to you. The first way is to try out what which button, which function does, find out what you can do with it, the eternal winning story of trial and error, you can and will only make errors when you try, but if you don’t try, you’ll never learn anything.
The second way to get further is to obtain the needed information, is to always ask others for advice when something is unclear, for example here in the forum, or, as a variation to obtain the information, and this is the way you learn more and better, press the F1 key every time and try to work out the answer in the manual yourself before you ask others.
It has always been the case that before success, the ability to master something, learning, practicing, making mistakes and repeating the exercise has made the beginner a master, no one has ever learned to drive a truck on a bicycle!
And here you can find another tutorial, it is a very basic one intentionally made for kids, and it begins “on a zero knowledge level”, but I had fun watching it, really.
Michelist