Winterizing is removing any water that may freeze from the water and drain lines. The drains lines will drain themselves, except for the traps. Traps hold water in them to keep any sewer gas from making it's way back into the house. The best way to protect these are to use an RV antifreeze. Just pour it into the drain.
The water lines need to have the water blown out with compressed air. This may be best left to a plumber if you don't have the tools. You will need a fitting that hooks to the plumbing lines in order to blow the air into the lines. The valves get opening to release the pressure and any water in the lines.
