Your administrator may ask you to side-load the Norton Mobile Security app on your Android device. Side-loading is as alternative way to download and install apps, for instance, when you cannot download and install Android apps from Google Play. Your administrator must provide you with instructions on where and how to access the Norton Mobile Security app. However, before you can install the app, you must enable the Unknown sources option on your Android device.
Enable Unknown sources option on Android
On your Android device, tap Settings and then scroll to and tap Security.
Under Security, go to Device administration and enable the option Unknown sources.
Follow the instructions provided by your administer to complete the Norton Mobile Security installation and enrollment process.