Note on the screen shot below that "Alexander, Robert" has been selected within the phone book. At the time that his name was selected, his phone number and address appeared to the right. You may dial him by double-clicking on his phone number (or by clicking the blue telephone icon has appeared at the top right of the screen, to the left of the stopwatch).
To make a new Phonebook entry, you would select the light bulb icon at the top of the Phonebook. To search the Phonebook for all records containing a particular word or phrase, you would enter that word or phrase into the small box to the right of that icon.