I recently bought an stm32 board to start learning and found the datasheet to be complete gobble-de-gook. I have a feeling there is a lot fundamentals I need to learn before the sheet starts to make sense.
Asking questions on the manufacturer's forum is useful to because you can typically get an application engineer to respond.
Have a look at Atmel/Microchip's AVR documentation, it's worlds better. That plus avrlibc and a few tutorials and you're golden.
Later jump in to microcrontrollers.
I used to teach a class called Electronics for Artists at a local maker space. This process worked well for that.