First go ahead to the Google Play Store and download a screen recording application. There are tons to choose from but I recommend AZ Screen recorder. Now record your screen. Once you're done recording, import it to this video editing application called Kinemaster. Now download this application called Screener from the Play Store. Take a blank image and add it to a phone frame (watch the video to find out how). Now just follow the steps mentioned in the above video, to make your screenrecordings look awesome!