I think winterizing was the hardest part of all the new things we had to learn with an RV.
Many use an oilless air compressor to, first, blow water out of the lines when we add the red antifreeze to all of the lines. The process isn't hard but you will need some things to do it.
You'll need to determine if your water pump has the winterizing valve already installed. (If it doesn't, it's not hard to install one and they should have the kits at almost all RV stores.)
This is good video to watch