Turn on the USB debugging mode, and connect your phone to the computer, then click the button "root" and now what you have to do is just waiting for the root result. Forget the complex and troublesome tutorials, everyone can control it easily.
After rooting you may get chinese SU. So go to google play store and install your favourite SU in English and update its libraries.
After that Start your English SU installed by you recently and go to its options to remove the older Chinese SU.
DOWNLOAD ROOTING SOFTWARE FOR LG G PRO LITE FROM HERE