Fall prep

Question:

I am starting the Fall prepare kit I have ordered from you and my thermometer reads at 20, I also am feeding the fish with the free food that came with the kit. I also put the net over to catch the leaves. When do I drain 50% and how do I drain the pond. When do I put the aerator and heater in? How do I disconnect the filter and pump? When do I shut it down or do I?