To the OP, I am still learning how to do all of this. I often don’t even know what anything is called, so directions with proper terminology aren’t always useful. Ha!
I had a similar issue. Here are some things to check. This said, I am not familiar with your particular motorhome, but I do have a class C.
There should be a couple of drains under your unit. Mine are blue plastic. They look like long straws. One has (or should have) a screw-on cap.
If you think about where those tubes come from, look in one of your outside compartments on top of the drains (tubes). My motorhome has a lever that I can turn up or sideways. It is attached to one of the tubes. When it is turned sideways (or perpendicular), that blocks the flow of water from the fresh water tank. If it’s turned up and down (parallel) to the tubes, it lets the water out (drains the tanks).
Something else to check is whether the anode (it’s a metal rod that gets screwed into the hot water heater) is not screwed on. Depending on whether they bypassed the hot water heater when they winterized or not, water may be pouring out of your water heater if the anode is not in properly.
Hope that helps!