Here’s a brief overview of how it works:
At the beginning of each round, players will fight to capture a central zone. Once the zone is captured, your team will deploy the Breaker. As players work to deploy the Breaker, the zone can be contested, resulting in an epic tug-of-war between the two teams. Once the Breaker is captured, it will be used to assault and hack the enemy team’s Vault.If you hack the enemy team’s Vault, you win the round. If you fail to hack the enemy team’s Vault within the round time limit, you lose. If you are in the process of hacking the enemy team’s Vault when time runs out, you will enter Sudden Death until you either hack the Vault, or the enemy removes all your progress.First team to win three rounds takes the match.Breakthrough will first be available as the Weekly Featured Playlist for the week of September 25. Then, it will be added to the Competitive playlist starting October 2. Owners of Destiny 2: Forsaken may begin to play Breakthrough in Private Matches on September 25 as well.
This was covered in the new This Week at Bungie article, which you can find here.
Additionally, Bungie covered several bases and summaries of what happened throughout the week. A few hotfixes were deployed, bugs were acknowledged, and the usual community awareness campaign where they display sweet player footage of incredible feats.