http://www.pcgamer.com/destiny-2-early-access-beta-preloads-are-now-live/

The Destiny 2 PC beta is set to begin in just a few days: August 29, specifically, or August 28 if you've preordered the game—or happen to be a lucky member of the PC Gamer Club. And if you're among that crowd of early go-getters, you can actually start preloading the game right now. 

Destiny 2 is available exclusively through Battle.net, so fire it up, select Destiny 2 from the list of games, and then hit the big blue "Install" button. If you preordered from a retailer rather than online, you'll need to redeem your "Bungie code" at bungie.net/redeem to get your beta early access code.