Brand new Steam customers should be automatically linked during account creation. If you have not yet created an account, please follow the steps in this FAQ.
After completing account creation, you'll be redirected back to the launcher, and should be automatically signed in.
If your account has been successfully linked, when logged out of the launcher, you should see a 'Steam log in' button.
Customers who already have a Frontier account, and wish to link to Steam, should see a 'Link account' button in the launcher when logged out via 'options':
Following this prompt will redirect you to sign in with your Steam account credentials.
If no 'Link Account' option appears, you can also link via https://www.frontierstore.net/
Log in and go to your account dashboard, using the orange icon at the top right of the page. Navigate to 'Partner Keys' from the pane on the left. Click the green 'Sign in through Steam' button:
Note that this is purely to link your account. You won't have a partner key to claim for ED or any of its DLC if you made your purchase through Steam.
If you experience any issues with this process, please do send in a ticket to our Customer Support Team via the button at the bottom of this page and the support team will be able to assist you further.