I have installed a couple of EMS systems.
I suggest that you purchase about 5 or 6 feet of 6/3 w/ground cable or what ever length you deem necessary.
Start by making sure you are disconnected from shore power and generator off.
Remove your breaker panel, disconnect the two #6 wires from the main breaker, white neutral and ground wires.
Attach one end of the cable that you bought in the places where your disconnected from the breakers, neutral and ground.
Then attach the other end of that cable to the out side of the EMS and the original cable that you disconnected to the in side of the EMS.
If you have other questions just ask them here on the forum.
Oh, and I moved your post to the electrical forum.
Peace
Dave