Article: APK stands for Application Package File; it's the package file format used to install software onto your Android's operating system. By default, you can't install APK from unknown sources. To enable installation, go to "Security" and tick the box marked "Unknown Sources." Once you have enabled installation, you can download the APK file directly to your Android. You can also search for "Flappy Bird APK" and find the best option to download. Either download it directly onto your Android or download it on your PC and then transfer it to your mobile using a USB transfer or Bluetooth.    {"smallUrl":"https:\/\/www.wikihow.com\/images\/thumb\/f\/f2\/Get-Flappy-Bird-on-Android-Step-2Bullet1.jpg\/v4-460px-Get-Flappy-Bird-on-Android-Step-2Bullet1.jpg","bigUrl":"\/images\/thumb\/f\/f2\/Get-Flappy-Bird-on-Android-Step-2Bullet1.jpg\/aid4075285-v4-728px-Get-Flappy-Bird-on-Android-Step-2Bullet1.jpg","smallWidth":460,"smallHeight":292,"bigWidth":"728","bigHeight":"462","licensing":"<div class=\"mw-parser-output\"><p>License: <a rel=\"nofollow\" class=\"external text\" href=\"https:\/\/creativecommons.org\/licenses\/by-nc-sa\/3.0\/\">Creative Commons<\/a><br>\n<\/p><p><br \/>\n<\/p><\/div>"} Open your Android's File Manager and find the file. If you downloaded the application directly onto your phone, then you will find it in the "download" section. If you downloaded it from your PC, then you will find it wherever you chose to save it. Once you have located the APK file, simply select it. You can now enjoy Flappy Bird on your Android!

What is a summary?
Enable APK installation. Download the APK file. Locate the APK file. Install the APK file.