I introduced the keyWentUp, the other key codes and how to add a sound to their project to my students at the end of L12. Give the following directions to your students. I am sure they will be able to complete the incomplete program.
Check out this program: https://studio.code.org/projects/gamelab/SvnH4ECh7MPqW3gcMuttvLg8cfvVY_fbTZXDotOPABQ
Create a new Game Lab project and complete the program.
Use this link to figure out the key codes: https://keycode.info/