Here you go:
https://imgur.com/a/E5lSaNotice that if you click on it, you should be able to edit that field. Make sure you're first working on a copy derived from the original or you'll overwrite the original scroll (which will change EVERY single copy of that scroll in the game).
To access that side panel with a custom scroll created, follow these steps:
- Go to the Root Templates tab (or open it up)
- Look for the cat summoning scroll (usually begins with "Scroll")
- Right click on it > Create new from selected
- Leave everything as is (I usually edit the new root template afterwards, personal taste) but change the name to something else under tab 4 (The engine will give you a red message warning you there's already an existing root template with the name it starts with. Just put something like "Hacked" or "Modified" at the end of the name and you're good).
- It'll then create the root template for you with all the stats and whatnot already linked.
- Right-click on your new root template > Open for Edit
- You'll get the sidebar with all the info you need there + that Item State section.
Let me know if that clarifies it

Cheers!
.:Quick edit:.
I'm assuming you haven't created anything, hence the step by step stuff. Just skip it if you already know the process :P