To call someone, do one of the following:
From the left, tap the forth icon, enter the person’s phone number, and then tap Call.
To call someone on their work or mobile number, from the left, tap the second icon to get to the Contacts screen. Find the person in your Contacts list or type their name in the search box. When you find the contact, tap their name, and then either their work or mobile number. This will call the person on their work line or mobile phone.