Enable USB Debugging Mode on the Android

Make sure Developer Options is enabled.

Go to Settings -> Developer Options.

Enable USB debugging by checking this option.

Enable Developer Options on Android KitKat 4.4

Go to Settings -> About phone

Tap on Build Number several times (7x) till the message shows "You are now a Developer" or "Developer mode has been enabled".

To check if its enabled already. Go to Settings -> Developer options would be visible.

Universal Cellphone Signal Booster SP-2 Sticker Placement

Samsung Galaxy S4

Samsung Galaxy Note 3