By pressing the wires into the insulation displacement connector with (ideally) the correct tool or failing that a very thin bladed screwdriver.
1 wire to 2 and other to 5
Correctly wired. Did you replace the frontplate at the master before testing at the extension?
Plug a phone in and see if you get dial tone.
It was just a long shot. You either need to get somebody in to sort you wiring out or go for plan B, powerline adaptors.