You should be able to create an account on the
Larian Vault site now. That was described in the last
D:OS 2 Kickstarter update in regards to claiming a copy of the D:OS Enhanced Edition, for those with it as a tier reward or add-on.
Basically, log in or create an account on the Vault, then click on 'D:OS2 Kickstarter', fill in your Paypal email address and click on the Link button.
If the tier you backed included a copy of the EE, you can choose a Steam or GOG key in the 'Your choices & input' section.