How I dewinterize
This FAQ has a complete guide to dewinterizing.
If you can not find your low point drains or your fresh water tank stopcock, then you might want to think about making an appointment with your local RV shop to do it for you (ask if you can watch).
They also have classes for new owners and you might be able to get scheduled for one. Expect to pay something for the training.
Watch YouTube videos and you may learn enough to do it yourself.
Lou and Laura with Bella - German Short Hair Pointer
2008 GMC Sierra 2500HD Crewcab SB Allison Duramax
2010 Flagstaff 8526RLWS - Superglide 3300
HAM CALLSIGN - KC3FFW