Go to the BP_RTSPawn and copy the video below.

Then go to the BP_MasterPreview and copy the video below.

Then in the BP_RTSPawn replace the node in your code with the node shown in the image below, location at the top of the image.

Open the E_ResourceNames from the Content Browser and add a new entry for gold like the image below.

Open the BP_MasterBuilding and copy the videos below.

Open the BP_HUDResources and copy the video below, to change the resource icon select it and in the Details panel you can change the texture it uses.

Next open the BP_HUDBuildingMenu and copy the video below.

Then go back to the BP_RTSPawn and copy the video below, then copy the image below by adding in the highlighted node.

Then copy the videos below to create the new resource blueprint.

Then open the BP_AIPlayer blueprint and copy the video below.

You can now place your new resource blueprint in the level, you will need to set a unit to be able to harvest that resource, this can be done in the unit’s blueprint using the Resource Unit Can Collect setting.

Then you will need to set a building for the resources to be dropped off at, this can be done in the building’s blueprint in the Class Defaults using the Resource Type Drop Off setting, make sure Is Building Resource Drop Off is also ticked on.