I don't know that river personally, but have seen a lot of photos, and it looks like a good river for SUP. Not sure if that are any big drops in there - you probably don't want to run those as a beginner, unless you're an adrenaline junkie.
Make sure to start practicing on the easy stretches.
Use a PFD, helmet, leash with emergency release (if you have a quick release on your PFD belt, that works), good shoes, and possibly shin protection.
When falling off the board, try to fall flat - what goes up must come down, and if you fall in with your feet down, those feet will sink deep, and run a real danger of getting entrapped.
Plastic boards work pretty well, but are terrible to carry around, so unless the put-in and take-out are close to your car and there are no portages, you probably want to go inflatable.
Enjoy and please let us know here how it went