Needing help? I thought so. I had this problem yesterday when I downloaded the big item pack. I forgot to copy and paste in the .cfg.
First, go to C:>FeralHeart>Media>Items. After you download the items, paste them in here. Now, look for the items.cfg. Open it up in notepad, and then click edit>select all. Click randomly (right click), and click copy. Now, go to C:>FeralHeart. Scroll down until you find items.cfg. Open that one in notepad, and then paste all the codes. Go into the game, and you'll see them. Do the same thing, but with massmarkings.