Held Items & Pet Companions

[Dinocanid]

Can someone explain to me a bit more of how I use this? I followed the tutorial, but I'm confused about what you put in the item image field in the adminCP when making the item, and once I get the item in my inventory I can't use it, it just says N/A. Also, where would I put the "img src" codes? In class_ownedadoptable?