Chosen Solution

Won’t move forward or reverse but when you lift the rear end the tires turn

Heidi, I am thinking it could be one of two things; you need to push back in a bar in the back that disengages the transmission, or, and more likely, you may not have gotten the pin or key back in when when you fixed the flat tire. Did you see a little pin that slides in along the axle?

This video may help: https://www.youtube.com/watch?v=YC4LnrfE