When you need to control a DC motor (such as a DC linear actuator) you usually need to be able to swap the polarity on the wires going to the motor.
A double pole, double throw switch is used for this purpose but you have to wire it up correctly to reverse the polarity going to the linear actuator.
Step 1: Required materials
You need the following materials:
-DPDT rocker switch
-insulated disconnect terminals (female) x 6
-wire cutter/crimper/stripper tool
-a linear actuator or DC motor to control