How to: Install app from a link
You might be sent a link to your email or device that ends in .apk. Similar to how .doc files are Word Document files - .apk files are simply Android apps!
To install an Android app from a link:
Ensure you have an Android Device
Unlock your Android device and go to Settings
Click on Security (could be different depending on Android version)
Scroll until you find Unknown Sources under Device Administration and Enable
Open the link sent to you on your Android Device
Click Download
The .apk will download to your default downloads folder
Click Open and install the app following the prompts.