that helped me out a lot when i was starting out, some essential concepts are done well, the later stuff is rubbish really as is most 2p2 strategy, you'll definitely find some good stuff on that page though!
Reading some good books is probably one of the best ways. Ed Miller writes really nice logical ways to think through hands. Free route is to check for videos on YouTube. I make some and there are others out there as well. My channel is unnexceptionalrounder so you can check that out if you want but for just starting out, books are pretty clutch.