The Octatrack is the only Elektron box I have.
I learned by searching for and watching video tutorials, as well as following tutorials in the manual.
The key is to focus on learning one thing at a time. Trying to learn everything all at once doesn’t work - at least not for me. For example, I focused on learning just how to use the pickup machines. Then I later learned how to use the audio editor for a flex machine - specifically to slice audio. Focus on one topic at a time.
Most of my learning has also been by trial and error.