How do I auto level the Wanhao Duplicator i3 V2.1

Hey everyone. I purchased the I3 Duplicator V2.1 4 months ago, I am getting comfortable using the printer, however levelling the bed is starting to put me off printing as it's becoming a pain to do.

I've seen in this post that it's possible to auto level bed. I have found the Z Probe available in my region here but I have no idea how to begin installing it and flashing the firmware.

Could someone explain in relatively simple steps on how to achieve this?