From the home screen, tap Phone (located in the lower-left).
From the Keypad tab, enter a 10-digit number then tap the Phone icon. To place a call from the Contacts list, tap the Contacts tab (located in the upper-right), then tap the appropriate number from the corresponding contact. To increase call volume, tap the extra volume / amplifier icon (located in the upper-right). Refer to Extra Call Volume for assistance.