Instructions:
1. Download and install Kingo Root (com.kingoapp.apk) from "https://www.kingoapp.com/" on the device
2. Open "Kingo ROOT" and follow the instructions
3. After successfully rooting the device, uninstall the "Kingo ROOT" app and then turn off mobile data and Wi-Fi
4. By using a data cable and a PC, copy "SuperSU" apk file to a folder on the device and rename it to "Superuser.apk"
5. Open "ES File Explorer" and enable "Root Explorer"
6. Copy "SuperSU" apk file to "/system/app/"
7. Make sure permissions are "-rw-r--r--" (shown as "rw- r-- r--" in ES File Explorer's file properties) for "Superuser.apk"
8. Delete "KingoUser.apk" from "/system/app/"
9. Reboot the device
10. Open "SuperSU" and follow the instructions

Kingo Root leftovers to be deleted:
/data/dalvik-cache/system@app@KingoUser.apk@classes.dex
/sdcard/com.kingroot.kinguser
/sdcard/Android/data/com.kingroot.kinguser
/sdcard/Android/obb/com.kingroot.kinguser
/sdcard/Android/data/kingoroot.supersu
/sdcard/kinguserdown