Position your pump as close as possible to your hot-water tank and about 2 feet below the bottom of your cold water tank. Connect the pipes from the hot water tank and the cold water tank to the inlet valves on the sides of the pump. Connect the pipes from the outlet valves on the top of the pump to the shower head.
Connect the power supply to your pump as per the instructions for your specific model. Make absolutely sure that the main power is shut off before attempting to attach your pump.
With the power off, allow water to run through the pipes and the pump. The pump should not be operated without water, since running the pump dry can cause damage. Once the pump is primed, apply power to your pump.