How do you add contacts to Panasonic kx-tcd545em?

To add contacts to the Panasonic KX-TCD545EM, first, press the "Phonebook" button on the handset. Then, select "Add" or "New Entry" and use the keypad to enter the name and phone number of the contact. After entering the details, confirm by pressing the "Save" or "OK" button. The contact will then be stored in the phonebook for future use.