Brand new Kodiak trailer - can't use toilet

From what I can see in the pictures, they simply didn't cut a hole in the tank. I don't see the "there is 1" from the toilet flange (exit of toilet tube) and a protrusion on the black tank (a shelf above the drain valve)."

If that's right, a side cutting bit on a Dremel would fix it in a jiffy. Don't let the cutout piece fall into the tank, it might eventually block the drain.