As said before the outlet of the fresh water tank is on the lower edge or bottom of the tank. Now, how to find it.
First, does your trailer have the underbelly covered? If not you should be able to access the tank outlet fairly easily. Albeit you'll be on your back looking up at the tank. If your lucky you can poke the water tube to the pump back down the hole and find it sticking out somewhere near the tank and reconnect it. If you have the underbelly covered that presents a more serious issue as you'll probably end up undoing it to find the tank. Lots of work laying on your back.
A piece of advice: if you do have to drop the covering remember if you end up with a couple of short screws where they go. I had to drop the covering on my Bullet a few years ago and did not realize that I had some shorter screws and went ahead and reinstalled the material and put two long screws where the short ones went and screwed holes right into the fresh water tank that was resting on the frame rail.
I was able to repair the tank but was a lot of aggravation that I didn't need.