Board Thread:Questions and Answers/@comment-184.56.4.94-20130914012854/@comment-5249040-20131031044824

You have the humble bundle page that you can download Delver from, correct? Somewhere on that page you can click "Click here for your Steam key". After that, click a grey Steam logo, and it should give you a key in green letters. Copy that key and paste that into the activate a product on Steam area. Insructions for that here. If that doesn't work you can send the developer a message on the TIGForums. If you need an image tutorial / further explanation I will glady help. :)