Having not done it myself... I'd guess you need to take out the right rear seat and rocket panel step-in plastic trim piece to pull up the carpet, take loose the center console so there's room to work, snake the wires on the side of the center hump, preferably with something protective over them going through the passenger foot space area like thin walled PVC tubing softened with a heat gun and flattened to conform to the hump slope while the wires are snaked through to the right placement, then pull them up through the console and attach to the switch, then put back all the parts you pulled up.
However the following diagram appears to show no wiring going that route which would explain the smooth appearance of the area, that more often the wiring would be routed under the rocker panel step plastic piece I referred to above, then taken sideways under the passenger seat to the center console.
http://www.justanswer.com/ford/4a6no-ford-explorer-4x4-installed-market-radio.html