1. Get out the rubber ball, we’re in solitary confinement.

Question

[Is this sentence grammatical?]

2. Put/place your handouts facedown on the desk.
3. Make the paper facedown on the desk.
4. Have the paper facedown on the desk.
[Which one is grammacal? Do you have some more useful similar expressions?]

Answer 1

1 is a comma splice. There needs to be a sentence break or a semicolon after "ball."

2 is fine.

3 and 4 will be fine when you replace the command verb with "Put" instead of "Make" or "Have."

You could also say, "Turn your papers face-down on your desk."