I would say the majority of the time would be spent designing the new UI window. Hooking up the Inventory slots to this new UI window instead of using the Equipment or Inventory windows is very basic blueprinting. There are only a few functions that are cleanly labeled and easy to understand for all skill levels in the InventoryManagementComponent that would need to be updated to reference your new UI Window when it generates the UI Slots instead of the Inventory Window.