From the Home screen, tap the Apps Key > Hangouts .
Tap to view your contacts list. It includes all of the Google Accounts you've added.
Tap the name of the person in your contacts list. If your friend is not yet on Hangouts, you can invite your friend via SMS.
OR
Tap the text field to enter a name, email, or number.
Tap Message and then enter your message.
Tap Send .