how to install a ruu

[saucratiz]

I downloaded the ruu file so I can undue a mix up and go back to stock and try to reroot how to I install the ruu

[sprintevo]

Connect the phone to USB. Chose charge only option. Then power off the phone. Power on holding volume down button.
You have a option of USB fast boot option, which you choose by moving the volume up button and select by power button. Then in your computer double click the RUU.
You will be done.