Homebrew Help

Can someone tell me how to add your Charisma modifier to homebrew armor I'm trying to make?

Modifier: Bonus->Subtype: Armored Armor Class->Ability Score: Cha

Thank you so much!

Update: It did nothing. Do I need to edit the base armor first?

After you add the modifier you have to resave the whole magic item. It can then take up to 20 minutes for your changes to take effect.

Do I need to set anything with the modifier? Like a fixed number?

No, you shouldn’t. Just set it up exactly how I did