#1 #3 AND #5 on front left to right #2 #4 and #6 on the rear bank left to right. You lucked out this time 4mm Allen wrench take the plastic cover off 8mm or 10mm hold the coils in and replace the far left front coil pack. And next month when the engine light returns replace the other five coils. Because P0320 indicates ignition primary not a specific Cly. I bet it is time for some spark plugs soon. As the plugs wear down there is more voltage needed to jump a spark across the wider gap. That extra voltage spark finds the shortest path to ground. burns thru the coil or coil extension. Good luck I always recommend plugs and 6 coils and my customers don't burn out the cat converters because of engine misfire.