Here are shortcuts for the most frequent addressbook actions:
You can edit a contact two ways:
Click once on the person's address card and you can edit the person's properties all in the same window.
Double-click on the contact's card and alter their details.
Right click on a contact and click Delete or select a contact and press the Delete on the toolbar.
Right click on a contact and select Send message to contact.
Double-click in any blank space in the contact manager to create a new address card. You can also use File->New->Contact or Ctrl+Shift+C