When a new Season begins, the first ten matches in any Competitive Playlist are your placement matches.
Placement matches help determine your skill level. After your placement matches are completed, you will be matched with opponents of a similar level when you join a Competitive Playlist.
At the end of the 10 placement matches, you may be a different Rank than the players you partied with. If you are rated a lower Rank than your friends, hop back on the field and do your best to climb up the ranks!
For more information check out our article: Party Matchmaking.