The valves should be turned as you see them to use the water heater. One line is cold water in, the other is hot (hopefully) water out.
During winterization you bypass the water heater by turning
all three valves 90 degrees, creating a "loop" before the water heater, so it doesn't have to be filled with anti freeze. You just drain the water heater by removing the anode.
Then, when winter is over, you turn them all back again. Replace anode, rinse with potable H2O, sterilize plumbing system, camp.
Repeat next year.
Or, maybe you don't, in Florida.
My dad has been RV'ing for 40 years, never winterized yet. Central valley of California stays above freezing..