To manage the address book settings you will need to click on the Settings option on the left-hand menu of the webmail interface once logged in.

From there you'll be taken to the Settings page and you can select the Manage Preferences

Once you've clicked on the contacts section you'll be presented with the following options to set your preferences:

Default address book: Will update with any groups/address books created
List contact as: Display name/first name last name/last name first name/last name, first name
Sorting column: Sort address book by Last name/first name/display name
Rows per page: Change the number of rows displayed on the page.
Skip alternative email addresses in autocompletion: Yes/no