The Stash lets a player deposit items that they want to be picked up by a Courier to take to the Warehouse.
The Stash can be crafted at the Sawmill or by the player.
Using the Stash
To use the Stash, right-click on it to bring up its inventory, which works like a chest. Put items in the stash and a Courier from the nearest Warehouse will pick them up and deposit them in the Warehouse for workers or your own requests.