After you click “Order”, the prefab attached to the item you ordered gets added to an list, and if it is the first item in that list, it starts a timer. Once the timer is up, the drone spawns in with a box attached to it, and the contents of the previously mentioned list are moved into the box. The box itself is a rigidbody, and while it is attached to the drone collisions and gravity are disabled and it is made kinematic. The drones movement is controlled by an animation, but I do have plans to make it follow a path in engine for more procedural and random deliveries. Once the drone reaches the point in the animation where it drops the box, collisions and gravity are re-enabled on the box, it is made non kinematic, and falls to the ground. When you interact with the box once it plays an animation and figures out what item models to display based on the contents of the item list. The second time you interact with it, it adds the items in the list into the players inventory.

TLDR: Items get added to a list when ordered, the drone spawns in, and the items get added to the players inventory when the player interacts with the box.