My fresh water drain is located on the outside of the coach, near the bottom of the side wall. It is a white spigot looking thing.
Not all coaches may have a fresh water tank drain, and if yours is like this, your best bet might be the low point drain - depending on where in the system it is located.
you can probably tell by looking at your tank and see how many hoses exit it. There should be a fill hose, a fill vent hose, the main discharge hose going to the water pump, and if you have a tank drain, a 4th hose.
The only thing that works on a RV is the owner...