I always like to drain out the tanks of any liquids. Drain the hot water heater tank, leaving the heater tank drain out. Flip the valves on the hot water tank, so it bypasses it.
Add 3-4 gals of pink mobile home antifreeze to the water tank.
Run the pump on the inside, running each water outlet. Don't forget to run the hand held shower head. I forgot one year, and it cracked. Be sure to run enough in the sink, toilet, shower, shower sink to cycle through any water that might be sitting in the P-Trap,, run about .5 gals in each location seems to work for me.
That seems to work for me.