Note, that this tutorial will work on other devices too, but you wouldn't find the Firmware in this tutorial, so before starting ask Google for you Firmware.
Watch the Video tutorial from bottom of the article or read the Written tutorial.
1. Install USB driver for Samsung SPH-L720T on your computer.
Download Samsung Galaxy S4 driver here
P.S. The drivers that Windows automatically installed doesn't fit our requirements, so you better install those from the link above.
2. Activate USB Debugging from Settings > Developer options > USB debugging, if you don't find Developer options under the System tab, you need to activate it.
How to activate Developer options on Samsung
