If I edit an existing multiplayer workshop map (The Plains - Building West Multiplayer) in the map editor so I have slightly different scenario options, how do I share that with someone so they can play it with me?

When we tried we had both downloaded the original from the steam workshop, and it looked like we were getting connected but he never did. I was hosting and I could play the map, and when we quit it showed the usual end of game stats for both of us, but that's it.