Basically supply L1 and L2 need to connect to the left and right lugs on the top of the contactor
Then you need to connect a smaller wire from the small lug on L1 to the overload/heater relay block below the contactor, another wire from the other side of the overload relay to the pressure switch then from the pressure switch to one of the terminals on the contactor coil.
The other end of the contactor coil will connect to your supply neutral.
If you have an auto/off switch separate from the pressure switch, that will need to be wired in series with the pressure switch side of the coil as well.
You also should verify that the heater in the overload relay is sized correctly for your motor.
