Bill Mason's Path of the Paddle series is the greatest instructional canoeing videos ever made. There have been some advances since, but this is still the quintessential resource on solo paddling on flatwater.
Yes, it's old but its content remains strong.
This is the solo whitewater part of the same Bill Mason video set. Whitewater paddling has added a considerable amount of nuance since these videos, but it's still the best starting place.
It's amazing that Bill was able to pull off all those runs in a wooden boat.