Here are a few that I consider easy to understand
Clip Studio also has their own channel and have very instructive and explanatory tutorials
Still, I believe that coming up with the right tip for you it's quite of a challenge, since I don't know what specific goal or tool you're expecting to use/learn, so it's a very broad or open answer that may not be what you're looking for, if you could narrow it a bit more, then maybe more useful tips could be delivered