Drumming

Drumming is the absolute foundation!
If you want freedom across the entire drum kit, this is the key. From beats to fills and everything in between, it starts with drumming. Let's start with the basics here as well: being able to alternate and play accents.
The bass drum and the hi-hat (played with the foot) are initially optional but very important to learn. The same goes for counting. The ultimate goal is to be able to play the entire exercise continuously while counting, with the bass drum and hi-hat continuing. But practice, as always, in small steps. First drum a measure, then count along, and then learn to play the bass drum and hi-hat along. Believe me, once you get the hang of this...
I once had to learn this exercise from my drum teacher:
Thanks, Maarten!