Orders can be in one of many states, which are represented at the top of the Orders List View.
You can sort orders by:
All - Show all Orders of any state
Awaiting Processing - Recently received Orders
Alerted - Orders needing intervention to ship
Processing Shipment - Orders preparing Shipments
In Fulfillment - Orders on the floor
Shipped - Completed orders (most will have tracking numbers)
Canceled - A record of your canceled orders
Some elements of Orders can be edited while in certain states. Intervention is sometimes required with certain Orders (e.g. Alerted ones) to ensure that they can ship.