Pretty sure the 31FS doesnt have a place to pour water into the water tank. It only has a hose connection. By flipping the selector switches to city fill should fill the tank via the pressurized hose connection. In country fill mode you connect a a short hose (supplied by Jayco) and put it into a water bucket, the pump will then suck water from the bucket and fill the tank. (I have had to do this a few times). In NORMAL mode, you should be on the water pump.
What confuses me is you said all that happens is it pours out. You should have 3 drain valves; two inside the compartment (below the valve switches) and one on the outside. These need to be shut. Ensure all your faucets are turned off, even the shower outside. Then when you open a sink faucet the water pump should come on. (since you said the red water pump switch was in the ON position and glowing red)
Its pretty simple. If it is not working, something is wrong with the pump.