There are two ways to add addresses to your address book. One is to manually type in all the information that you are adding, then click "Add Address". Or even better, click on icon below while the message is open:

To change an existing address in the Address Book, just click on the name of the address that you would like to change. Once you have opened the current information for that address, change whatever details that you wish to change and then click on the 'Update Address' button to save changes. If you have made changes to the Nickname a message will appear asking you if you would like to replace the existing address entry. Click on the OK button to update the address. Please note that if you click on the Cancel button, a new address will be created.

Recent Addresses is a list of the 30 most recently used addresses. When the check box 'Add addresses automatically' is checked, the From, CC, and BCC fields of any messages received by the user will be automatically added to the recent address list. When the "Add addresses you email" check box is checked, any email address that you send to will be automatically be added to this list if not already there.

Also when you view any email, there is also the RECENT icon (above). When you click on this icon the "From" address of the message is added to the recent address list.
 
To delete addresses in the Address Book or Recent Addresses, just select and click "Delete" in the "Edit Address Book Entry" window.