STEP 1-> First you need to download Kingo ROOT.apk file from google. you can download it from here https://root-apk.kingoapp.com
STEP 2->Now install this app into your android device.
To install this file first you need to click on Unknown Sources into your phone settings to install the Application.
STEP 3->Now Open Kingo ROOT app Click "One Click Root" to start the rooting process.
Waiting for a few seconds till the result screen appear.