Sounds like so much to learn..
1. Learn to use "Search" tab on blue bar above.. One major benefit of registering...
2. Read the entire owner's manual, or if you don't have one, try to get one.. Someone was offering pdf versions on a Disk for free recently..
3. Your toilet drains into "Black Water Holding Tank" under floor, which needs to be drained from side of trailer using sewer hose (3" flexible hose" with special fittings at each end) One end hooks to trailer, other end goes into sewer dump hole in ground.. (You did get a hose with the trailer??)
4. The valve to drain the tank (and the Black one will say SEWER or TOILET on side) has a black plastic knob on end of steel shaft. Pull to open (After all is connected..) and push to close..
Beyond that, you might want to try to find Robin Williams movie RV in theater or DVD rental (a little too soon, I think..) to see what can go wrong...
In Theory, there's no difference between Theory and Practice, but in Practice, there is usually a difference...