Go to the Black Desert Mobile Pre-Registration page: https://www.world.blackdesertm.com/Intro/prereg
Sign up for the newsletter, when you press "PRE-REGISTER", a popup will appear with text "Welcome, new Adventurer!".
At the bottom of that popup it says "Enjoy Black Desert on PC, XBOX, and PS4®!"
Select your Platform/Server and click "Play", you will get a coupon for the official website.
Go to the official website and register / login: https://www.blackdesertonline.com/
Go to the redeem page https://www.blackdesertonline.com/shop/redeem and redeem your coupon.
It will give you the Starter Pack (€9.99). It might take a couple minutes to show your game acces status.