The great Destiny 2 changeover has begun: Bungie's big shooter doesn't go live on Steam until October 1, but you can get your account ready for the move as of right now.
The process is simple. Go to bungie.net and click "get started," then select the account you want to move over (apparently you can also transfer your PS4 or Xbox One accounts if you want) and link them as prompted. That'll take you to an account review screen to confirm that this is something you actually want to do; assuming it is, click "continue," agree to the terms, make really super-duper sure you want to do this (again), confirm with Steam that this is all above-board, and then finally, you are done.
There's no hurry to get the transfer done, but you will want to do it: After October 1, Destiny 2 will be gone from Battle.net, and so will your account.
