As you walk in, there is a remote that controls mini splits. The remote is designed with one ac unit in mind. However, you can use it with multiple units.
To do so, simply get close to a unit with the remote and press power for on. Go to the next unit with the remote and press power twice. With the first press of power, the remote thinks it powered off the first unit, but it doesn't because it's not close enough. Simply go to every unit after and press power twice.
To turn off, it is the same process in reverse where you end up pressing power twice. Please return the remote to its home.