Voila,
As a result, only a select number of players will have access to Guided Games starting with the Nightfall on September 12. This allows Bungie to see how the system is working and to allow more players to enter based on how it works. The goal is to make sure everyone has a good experience.
Here are the plans Bungie laid out for the Guided Games system.
Nightfall Guided Games Beta: September 12th, 10AM
30-50% of players will be given seeker access, depending on clan participation in Destiny 2 during the first week.
Nightfall and Raid Guided Games: September 26th, 10AM
Target: 100% of players will be given seeker access.