You can create two types of bags in this project: backpack and belt. The logic of adding a new item is the same for the belt and the bag, the only difference is in the inventory: you can’t put the belt on the bag’s slot or bag on the belt’s slot. 

Here is how you can create a new bag:  

In the widget you can select the size of the inventory you want to have

In the blueprint you can select your own skeletal mesh that you want to use and add any other component 

Now you can add it to the DT_Items

You can add a bag by default in the ArmorEquipment, add a new array row and select your bag here: 

Set the name of the bag in the helper to bag_”n”, where n is the index of your bag (first bag will have “Bag_0”, second bag “Bag_1” and so on”. As 0 is already locked by us you need to set the index in the bags controller to 1. Make sure you don’t have any game saves. Close the project and delete the Saved folder in the folder with your project.