To add a new attribute, you must add an entry to the non-persistent and persistent character enums, such as “Current Charm” and “Maximum Charm”. If you want it to automatically consume or regenerate, you would also need to add enum entries for these values in the persistent character enum (“Charm Regeneration Rate”/”Charm Consumption Rate”).
You would then need to add these variables to AC_Attribute_Manager_Abstract. If you look at the Primary States > Change Non-Persistent Attribute subgraph in AC_Attribute_Manager_Advanced, you can follow the flow of other attributes like health to see how it gets updated. You would also need to add an entry for each to the correct array, so an entry of “Current Charm” in the non-persistent attributes array, “Maximum Charm” in the persistent character attributes array, etc. This will add it to the attributes list in the UI tab.
In UI_PlayerStats, you can duplicate one of the rows and change it to be your attribute to add it to the in-game UI.