The programs run on your mind, on the minds or others, on the egregore or in your DNA.
Anything can contain code, and anything has an energy flow. Instead of using powerplants which run turbines or water mills which produce electricity, then sending it in wires through transistors and diods, greys just hijack any bio-device and run the code on it.
You can send programs or make bots and run them in the air, because there's molecules there and those can contain code. Atoms also sping so you have a free energy source right there. With grey tech, anything you see is hardware which can run your software. Anything is a computer.