From a Home screen, tap Phone (located in the lower left).
If unavailable, swipe up or down from the center of the display then tap Phone.
From the 'CONTACTS' tab (upper-right), tap the Menu icon (upper-right).
Tap Speed dial.
From the 'Enter name or number' field, enter the name or 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 then tap the appropriate dial entry (e.g., 2, 3, 4, etc.)