note I was self-taught... and then received coaching.
When I was first getting started I had the fortune of being taught a bit and then kind of being set free to discover some things on my own. I certainly am grateful for some of those initial lessons though. I didn't have access however to instruction and had to self-teach. I watched pretty much anything I could get my hands on, and this all came before YouTube around 2000. All said, there are a ton of resources out there online for free. We even put some out there on our YouTube channel here --->

All said, there were times in my paddling where I sought out (and still do) professional level coaching or time spent with paddlers better than me who can, and are willing, to give critical feedback. I'd say especially with the roll, hands on kinesthetic instruction from an excellent communicator will alleviate or never cause frustrations to occur to begin with.

Finally know that your pool roll will not translate to the river well if you do not introduce chaos and unpredictability into your practice. You have to simulate adversity in the pool realm to be ready for the river realm.

Hope that bit helps and good luck!

Chris Wing
H2o Dreams