Add an item to the top of the queue
1. Click on --- Top of the Queue ---.
2. Click on an item in the inventory, then click the Add button or double-click on the item in the inventory list.
⇒ To add additional units, keep clicking the Add button or double-clicking on the item in the inventory list.
Large orders
Pressing CTRL+SHIFT when clicking on the Add button will add as many of that item as possible. This also works if you press CTRL+SHIFT and double click on the item.