2.) Cut the 12v cable coming out of the power supply approximately 12 inches away from the power
supply. The 12v cable is the one that does not plug into the wall.
The instructions say to cut the 12v cable to approximately 12 inches. This is because you don't need all the excess cable. Do you have a pair of wire cutters? Scissors aren't made to cut wire, but they'll work if that's all you have. I would strongly suggest a pair of wire cutters/strippers, though. You'll be doing a fair bit of wire cutting/stripping and it helps to have the right tool. They are usually $10 or less from your local hardware store.
Be sure to follow the instructions verbatim. If you do so, everything will come together perfectly in the end.
If you need additional help, don't hesitate to ask.
-Prusa i3 MK2s
-Airwolf HD2x w/ E3D v6 + Volcano
-Custom built Solidoodle 3 clone w/ E3D v6+ Volcano -Solidoodle Press w/ E3D Lite6
Filastruder #1577