Two ways to obtain access to the Destiny 2 beta:
If you pre ordered Destiny 2 (Release Date September 6th, 2017) for Xbox one, PS4, and PC. You were given early access to the private beta.
Destiny 2 PS4 Beta early access start time - July 18, 10 AM PST
Destiny 2 Xbox One Beta early access start time - July 19, 10 AM PST
Destiny 2 PC Beta start time - Late August
If you did not pre order, The Destiny 2 servers will be open to everyone July 21, 10 AM PST - July 23, 9 PM PST (All Systems)
Destiny 2 beta download size
The download size for the PS4 beta is 15GB, and 13GB on Xbox One.
Full game details from the developers Bungie:
Homecoming: The opening mission and cinematics from Destiny 2’s Red War story campaign
Countdown: Battle other Guardians in a brand new Crucible mode. Attack or Defend the base on a new map custom-built to support this new game type.
Control: The original standard for Crucible combat is back, with some changes. Control the zones on another new map built with this objective in mind.
The Inverted Spire: Strike at the heart of a Vex stronghold. Bring two willing allies, or let Matchmaking introduce you to a Fireteam of Guardians.
New Subclasses: The new fighting style for each Class will be at the ready. Choose from the Dawnblade and Voidwalker for the Warlock, Arcstrider and Gunslinger for Hunters, or Sentinel and Striker for the Titan.
Weapons and armour: the beta will feature over 20 weapons, including three Exotics (Sweet Business, Sunshot, and Risk Runner), and three armour sets for each class, for a total of nine.
Two of the game's biggest complaints are grinding for “Loot”. (Powerful armor and weapons) people who played the original game will not have anything carry over.
The second complaint has been the frame rate. The standard now for which video games are run on is 60 fps, while Destiny 2 runs on 30 fps. Despite the fact, it's still a beautiful game and should satisfy your gaming needs. If you enjoyed the first installment, you will have a great time playing this sequel.