Your customers have various areas relating to their own purchases and orders on commerce, along with areas to manage their own details such as addresses and alternative contacts on the system. By default these would be access under the store tab, which is what will be shown in this step. Please note, you may have moved these items using the menu manager.
Under the orders tab you will see any orders which are still awaiting action. This may be that they are awaiting approval, or that they are awaiting payment or cancellation from the customer.
Under manage purchases, you will be able to view all the purchases that you have made on the system. This is where you can cancel a recurring item if you wish, and see any other detail (such as a downloadable item).
From here you can view/change your Primary billing and shipping addresses
The personal information section will allow you to change your custom details such as you name and phone number.
From here you will see alternative contacts which have been set up on your account. These are users who a customer can set to be able to manage the account at their behalf, such as being able to request support.
Clicking on Add New Contact will allow you to add a new alternative contact within the system.