(Taken from Kingmaker kickstart and yes, these steps did work for me):
For me these things work:
Transferring Your Pledge
First things first: the only way to get your hands on your rewards is to “transfer your pledge” from Kickstarter to owlcatgames.com. This bit of technical jargon basically means telling our website that you are a backer and you would like to download your game. Here’s what you need to do:
1. Register an account at https://owlcatgames.com/preorder. Look for the “Sign up” button in the top right corner of the screen:
2. Once registered, enter your personal account area by clicking on your e-mail address in the same top right corner of the screen:
3. Enter the Kickstarter e-mail address you first used to back our game in the “Get Your Transfer Code” field. If you get an error message here – don’t worry! Read the “Technical Issues” section below.
4. Open your e-mail in a different tab or browser window. You will receive a letter with a link and all necessary instructions. Please, make sure to check in your spam-folder! While still logged into owlcatgames.com, click the link. A pop-up will open and ask you to transfer your pledge. If this shows the amount you have pledged on Kickstarter, tick the checkbox for confirmation and then finalize your pledge.
5. Your digital rewards should now be available under your owlcatgames.com account! Click the ‘Get your Digital Download’ button, then choose your platform. For more details on platforms and entering your digital game codes in Steam and GoG, consult our Update #60.
So you DO NOT get code in your e-mail. You get it for https://owlcatgames.com/preorder/account <= go to the right side (Get your digital download) and press it. It will open and you will see key or multiple keys, insert your game key first (as suggested) in Steam or GoG. After you have used it insert rest of the keys if there are other ones.
IF that do not help try to contact Mortheim: email@example.com