The way that people use video call is through Android using Google Hangouts. You have to first download the Hangouts App from the Google Play area. The particular app my be already installed on the device you are using.
You then sign into the Hangouts area. Click the button on the upper right hand corner of the app from the right to left area to bring up the Hangout screen. You then look for the person you want to chat with on video. Then you select the call video or video call button.