It should be pretty simple. Here is a link to your trailer. Look at the 17:45 mark and see if that looks like your trailer.
If so you don't need to find the pump because the convenience center has it set up for you. The top lever is to winterize and will set it up so the pump will pull water from the water inlet (I can't read the writing clearly). The bottom lever is for bypass. With it set to bypass the water heater is bypassed. Bypass the water heater, set it to winterize, connect a short piece of hose (with the make end still attached) into a bottle of pink stuff and into the water inlet. Go inside and turn on the water pump..it should begin pulling antifreeze into the trailer when you open the faucets. Begin with the faucet furthest from the pump and let it run until the pink comes out both hot and cold sides (let enough run through to fill the p traps). It might tank a moment for the pump to prime. Repeat with the other faucets as you get closer to the pump. Don't forget the shower, outside shower, toilet (just depress the pedal like you were flushing and leave enough in the toilet to cover the rubber seal) and black tank flush line. I just blow out my black tank line but you can attach a hose from the outside shower outlet, connect it to the black tank rinse inlet and turn it on. Now, let's hope that is what your trailer looks like.