I was just wondering how I equip the cards I bought from the Nightmare pack and other packs. I can't seem to find them in my inventory. It shows only my started deck. Am I doing something wrong?
There are multiple circles over your deck screen, representing all the schools of magic.
I assume you are talking about the treasure cards. Click the golden treasure card button and you'll see all your treasure cards you have in your posession, including the slots available for them.