1. Go to Contacts. From the bottom menu, tap the “Contacts” menu
2. Select the person to call. From your contact list, scroll up or down to find the person you’d like to call. Tap on the name once you’ve found it.
3. Call with Viber Out. The selected contact will be displayed on your screen, with his name, photo (if available), and phone numbers.
If your contact has a Viber account, you don’t need to pay anything to reach him. Viber to Viber calls are free. Just tap the “Free Call” button to initiate the call.
If your contact doesn’t have a Viber account, you need to use Viber Out to call him. Tap the “Viber Out” call button instead to initiate the call. You need to have enough Viber Out credits to have the call.
Link Source : WikiHow
