This is really simply, however! Myself and a friend discovered that they might've made an anti-boost measure built in to the match-making.
If you quit out it won't count, and if you just delete your base after the match starts, it doesn't count either!(unless it was glitchy)
We tested various times, and it seems you need to be in the match at least 3 minutes for it to count. (Could use more testing)
You don't have to win!
Multiplayer is very easy to find, it's right on the main menu and there are some fun options to choose from at the present time. If you want to play a complete game, Rumble is a fun choice to learn the units as you start with max research and unlimited resources.