The Short Story
To enable Unknown Sources in your phone, simply go to the Settings app, scroll down to Security, and then scroll down to ‘Unknown Sources.’ Tapping this option will enable you to install apps that are outside the Play Store ecosystem.
The Long Story
If you’ve been reading AndroidGuys for a while you’ve probably heard the term “Sideloading.” What this refers to is the process of installing an application using a method other than through Google’s Play Store. Consulting the always-accurate Urban Dictionary, we find the following definition:
Sideloading: To download a file, esp. an application, to a smartphone or other electronic device outside of the accepted or usual channels.
Basically, instead of relying on the Play Store to download and install an app for you, you’re taking control of that process by downloading the file to your phone’s internal storage (or SD card) and then initiating the install process using Android’s built-in Package Installer.
By enabling the use of Unknown Sources, as described above, you’re expanding your selection of apps to nearly any file with the extension ‘.apk.’ Now, granted, I wouldn’t recommend going out and installing every single APK you see on XDA Developers, but sometimes it can be useful (such is the case when installing Amazon Underground, for instance.
Installing a third party app is as simple as can be, really:
- Download the app – using Amazon Underground as an example, navigate to the link above and download the APK.
- From your notification shade (or your Downloads app, if you accidentally dismiss the notification) tap on the APK and the Android Package Installer will launch.
- Tap “Install.”
Pretty simple, no?