1st oil change - How does the remote drain hose work?

[evilblackdog]

I'm doing the first oil change on a new to me 325 skid steer. I unscrewed the plug from the remote oil drain expecting oil to come out but there is nothing. I opened the little access door around it but can't really figure it out and everything is all rusty because it was sitting in a bunch of wet mud. This is what it looks like now with the plug out and the door off. https://imgur.com/a/OK2GLdi