Within the Shared/Apps folder of Commerce Manager, there are a series of XML UI config files and user controls which power the Commerce Manager UI.

In some cases, you can customize the XML configuration file directly to hide or show additional columns within the list views. The config file you are looking for is under:

Shared\Apps\Order\Config\View\Grids\Order-List.xml

Once you assess whether or not you can add or remove items directly from this configuration file, you may have to create additional user controls to load external data or related data to display in that list.

One such example in that file is the Order Status column - you can see that the out of the box code is loading a built in EPiServer user control which is in a nearby folder:

					<Column width="150" allowSorting="true" dataField="Status"  headingText="{SharedStrings:Status}" Align="Center" columnType="CustomTemplate">
						<Template id="OrderStatusTemplate" controlUrl="GridTemplates/OrderStatusTemplate.ascx"></Template>
					</Column>

Thus, you can take the same route to add additional columns by creating your own user controls and referencing them in the XML configuration files. These controls could extend existing EPiServer Commerce controls, or be entirely custom written.

Once you have these customizations, it's important to manage their deployment (this depends on if you have automated Commerce Manager or not) and make sure you keep track of them going forward if you upgrade.

This article has some great details on common customizations:

http://world.episerver.com/articles/Items/Customizations-of-EPiServer-Commerce-Manager-/

Hope this helps,

/Matt