Using ScratchJr, create a background like this:
Then, place Scratch or any character of your choice at the top of the first mountain.
Program scratch to go down the mountain, then up and then down again.
Tip 1: The action of going down the mountain is compound by two different actions (right & down).
Tip 2: Use loops. There should be 3 loops, one for each part of the route (going down the mountain, going up the mountain, going down the mountain).