1. How do you maintain your balance on a C canoe?
This comes with practice and experience, just put in the hours and you'll get it. the key is to keep your CG inside the boat until you are paddling when you throw your CG out.
2. How do you steer the boat?
With a J-stroke (although I personally just prefer to pull the water under the boat and let the exit be a natural 'J')
the trick is to control how the stern moves, not the bow.
3. How long is the paddle?
up to your eybrows or the bridge of your nose, depending on whether you are using a post 2000 or pre 2000 model where the boats are of different width.