And this is a setup for a dual-acting cylinder.
In this case, there is always air flow thru the valve, wether its plugged in or not. Once you connect an air pressure line to the valve via the "quick connect", it will send air down thru the #1 line I have marked.
Once the valve recieves power via a motion sensor/pressure mat, it will reverse airflow from the #1 line and push air thru the #2 line. At the same time, the air that was in the #1 line goes out thru the exhaust.
When power is cut off from the valve it reverses the air flow again, and sends air back into the #1 line, while releasing the air that was just in the #2 line thru the exhaust.
Typically, when the valve is in the off position(and hearing how you want your prop to work), you want the piston itself to be down(or inside the cyliner). If so, then you want to connect your air lines in the opposite order as this diagram shows.
In other words, the way this diagram shows, when the valve is off, the piston is in the out position because air is always in the #1 line. All you have to do is connect your #1 line to the front/top of cylinder rather than at the bottom like this diagram shows.