Help Me ! To Install LEDE Firmware On My TP-Link TD-W8968 V3 Router

Hi ! Every One !
As i have try to install the LEDE Firmware On My TP-Link TD-W8968 V3 Router but am getting this error.

Image uploading failed. The selected file contains an illegal image

Will You Pls Guide me Step By Step To Install this Fabulous Firmware on My Router

Note : As i have search on internet how to install this but i cant figured out the correct procedure for installation?

Some Info About my Router:

Official LEDE Firmware TD-W8968

HWDATA

Stock Info:

Firmware Version: 1.0.5 Build 150512 Rel.42337
Hardware Version: TD-W8968 V3