This APP can control the 4-axis aircraft by WiFi on the Android smartphone, and also can get the real time video from the aircraft, and take the photo and save the video.

Make sure that third-party apps are allowed on your device: go to Menu->Settings->Security-> and check "Unknown Sources"

Tap the APK file. Allow the app any required permissions it asks for. Then, at the bottom of the installer window, click INSTALL.

You'll see a confirmation the app is installed. Now you'll see the app available in your list of installed apps.