Young Writers Society

First of all, I must tell you: It's not a book, it's a screenplay.
I'm having trouble establishing the overlying theme in my plot, which is a machine that allows people to enter a state of artificial dreaming in an attempt to better ready them for things like war or the CIA or other instances where a person would need to have quick problem solving and be able to notice key details in whatever situation they happen to be in. Whenever I come across an obstacle like data dumps in writing, I usually just take the SGU way out and introduce a new character who needs to have the concept explained to them. It's easy, but it's also boring and slightly cliché. Everyone in my plot already knows about the machine, as it's a very small cove of people. Because everyone in the story already knows everything there is to know, I just need to find a way to explain to the audience what the machine does. Should I do this through dialogue or action or both? I don't know :/ I need something D:

Show, don't tell.

Simply let the character use the machines as they normally would. Readers (and, in this case, watchers) will be able to figure it out just fine after awhile. Probably not as long as you think, either. Readers/watchers might not be able to explain exactly how it works, but they can get what it is and does. That's all they need.

Malfunctions are also a good way of showing more of the inner workings of the machine. Depending on how exactly the machine works, different malfunctions could occur, and these malfunctions would have different effects on the usage of the machine.

You could also occasionally show maintenance on the machine, and have some of the operators complain about certain features not functioning properly, or they suspect that X is acting up because of Y, or Z is out of alignment.