I’ve created a mod that tweaks the ChatBoxUI, however, when I create a mod, the ChatBoxUI file doesn’t gets cooked, the game loads the mod with no usable files in there.
But when I create a Total Conversion, those files gets cooked and uploaded and can be used.
To make a child of a parent class, click the blueprints button on the top bar and select create new class then search for the PrimalGameData_BP and create the child.