Invite everyone who plays Umbrella Corps actively!
Everyone needs players, let's make this game big! =)
Everyone can make Announcements so you can post when you're looking for players! =)
If you want people to join your match, I suggest you "Post an Announcement".
Try not to have your announcement linger in the archive (Delete it after 5-10 minutes).
Other players would most likely not see your post if you post it in "Discussions".
If you're REALLY desperate for players, you "could" try and Re-Announce the match 3 times.
Players may get annoyed if they see a notification pop up every minute, so don't overdo it.