Works much the same way as warehouses did in C3. The main difference is the improved control over the yard's operations through the use of the "Special Orders" screen. Using this screen you can make the following settings:
Accepting - This is the default setting. If you want to limit the amount of a item that your yard will accept, you can now do so through the use of a scroll button. You can set amounts from 0 to 3200 in 400 unit increments.
Not Accepting - Same as C3
Getting - You can tell the yard cartpusher exactly how of an item you want him to get. You cannot get items from another Storage Yard that has the same 'get' order.
Empty - You can select the items you want to empty from your yard. The cartpusher will then try to find another granary or storage yard to take the item. When emptying, a cartpusher will shift 400 units at a time.