If a Cub is going to be your first building experience, I whole heartedly recommend Great Planes. Their photo illustrated, step-by-step instructions and plans are second to none! Get it! Build it! You'll LOVE it!

PS. Build the clipped wing version! The full wing IMHO is way too much wing for this airplane. With the clipped wing, it will still float like a trainer, but it will be capable of some awesome aerobatics!