I am installing a new water pressure tank and am wiring up the pressure switch. It has 4 electric contact screws, the outside two are labeled L1 and L2. The middle two are M in a circle. The pump is wired 220. Which screw contact do I hook up to the service box and which to the pump, and do I use all 4 since I am using 220--two line and two load?

L = Line, so the two live feeds form the service disconnect switch connect here

M = Motor, so the two load wires going to the motor connect here.