Welcome Brian! Don't let the lack of space deter you. Dewey's diagram above is a very practical way to enjoy your trains without eating up your floor space. Here's a link to a video I made last year. I essentially built what Dewey was depicting. My office is about 15 by 15 and I managed to put up 072 corners. I only run one line though, I think his has dimensions for two tracks. Took me all of 2 or 3 weekends to throw it together and it was pretty cheap.
https://www.youtube.com/watch?v=NpKtws1fAuw
Good luck and don't hesitate to ask for help on the forums here. Really helpful group of people here.