From a Home screen, tap Phone (lower-left).
If unavailable, touch and swipe up or down then tap Phone.
From the CONTACTS tab (lower-right), tap the Menu icon .
Tap Speed dial numbers.
From the Name or number field, enter the name of number of the desired contact.
As the name or number is entered, a list of matching contacts may appear and can be selected at any time.
To change the speed dial number, tap the Dropdown menu icon located to the left of the field then select the desired number (e.g., 3, 4, 10, etc.)