As you can imagine I spent a lot of time searching through videos for good ones for learning, and I put the best ones in a playlist. It might save you some time. The embed is not much use, better to click where it says watch on youtube to get it on a youtube page showing the list.

I would not try the polyrhythms early on but it does strange things to your head and is well worth it eventually. Especially the 5/8 with 4/8 one.

Amy Naylor has a channel mostly using a Hang rather than a Rav. But it’s good anyway for the overall principles and she does good patterns and teaches well. Also she has the drum patterns she uses free on her website to download. This one is with a Rav but it might seem a bit not so good unless you heer the finished thing, which she only plays at the end, so if you skip to around 14:30 you can see that first.