How do I add Command Operations user created scenarios so I can access them on Steam?

Apologies if this has already been answered - how do I get a Steam key for the Core Engine? I only have Steam keys available for the scenario packs I bought.

LnLP has completed our store system to allow us to provide Steam Keys to our customers. The process is simple. 1) Login to your account on the LnLP Store (http://store.lnlpublishing.com) with your account Once you are logged in please go to your ACCOUNT section on the LnLP Store. You find it...