There is generally a short piece of flexible tubing not far from the water pump. That goes into your RV antifreeze jug, flip the lever near the fixed end of that tube and turn on the water pump. Then one at a time, open all faucets and flush toilet until you see antifreeze. Lever is like the one in this picture, not an exact likeness , but you get the idea.
Winterizing isn't too much different from model to model. Main thing if you're doing antifreeze is to get it into all you lines. Don't forget to drain fresh water tank and your ice maker, if you have one.
Hope this helps, others may chime in if I've omitted anything.
2015 Georgetown 329DS
2014 Chevy Equinox