This part of the orders screen contains all the information for any single order that has been selected from the top of the screen - such as products purchased, quantities, marketplace Order ID etc.
If an order only has 1 item on it - then changing the dropdown status for that item changes the status for that order. For example - marking an item as dispatched or refunded will complete an order.
For orders with multiple items - it is possible for those items to have different statuses (e.g. one pending, one dispatched). The entire order will not get marked as complete until all items have been marked as complete or refunded.
Marking an item for refund will launch a new dialog so the user can complete additional information about the refund.
If you want to view the actual order on the marketplace it was placed on you can do this by clicking on the Marketplace ID.
If you want to view customer information - then click on the View link next to the customer name.
You can view the product information by clicking on the product name.
You can also add your own note for that order by entering text in the note field and hitting the Add Note button. This note does not go to the marketplaces - it is for your own internal uses only.
You can view full order history by clicking on the Order History link.