Adding characters

I’m trying to add characters to a comic that does not have them (LOSH vol 2 #260) but do not have the ability to add characters OR creators in the Edit Comics screen. This is something I’ve done in the past with comics that I own but are incomplete in the database so why can’t I do it now?
Version 23.7.3

In your picture, right above Gerry Conway’s name as the writer, you’ll see that you have the option of “Core Creators” and “Custom Creators.”

You have it set to Core Creators. That means that you will get the Creator information delivered from the Core. Click on Custom Creators and you can add your own (and they will sync with your mobile app if you use that, too).

Click on “Custom Characters” to do the same for Characters.