So if I have two players that match up using FindMatchRequest, it creates an entry in the matches table in NoSQL. 

From there, how do I actually begin, play, and end that specific match (with the specific matchid)? Do I use that same matchid in a challenge?

To add an interesting sub-question, what do we actually know about the players returned in a FindMatchResponse? Can we be sure that these players are active, online, whatever? Or do we really only know that they sort-of-kind-of matched the "skill" we set in the FindMatchRequest? Because the documentation suggests that the players returned may not be online, which means I really can't start a game against them right now...