Step 6: Stopping, Turning and more
once you can go straight, practice stopping and getting on and off. this is the only time you will put weight onto the second bike - when you are stopped and getting on or off. as soon as you are moving you're riding like you did with one hand.
next practice turning. anytime the second bike seems to be getting off track, just lift up its front wheel for a moment and put it where it should be (a comfortable distance to your side)
when riding in the city, you'll also use the same lift-up-the-front-wheel trick when you are riding over potholes that might throw the second bike off track.
Now go have some fun!!