: If it is a Gibson 335 or similar type guitar, an easy solution is to: Place the north pickup volume/tone pots and any switches in the south holes and the south pickup volume/tone pots and any switches in the north holes from the front on the outside of the guitar body. Also, the pickup selector switch. Put a piece of aluminum foil over the surface of the guitar to protect it from scratches and any solder that may drop before putting the pots and switches in. Wire up the volume/tone pots and make all solder connections. Place the output jack in the opening for it and cut the wires for it a little longer then needed and solder them in place. Solder a couple of shielded pig tails on the V/T pots, for the pickups to hook up to, long enough to reach the pickup holes with no problem and mark them north and south. This will make a wired up harness to install through a pickup hole. When it is installed from the inside of the guitar, it will be turned over. Thus, the reason for placing the north stuff in the south holes and vice-versa. Then take a guitar string and run the ball end through each V/T, switches holes to one of the pickup holes and tie a piece of twisted fishing line to the ball. Pull the fishing line back through with the guitar string and leave it long enough at the pickup hole to tie to the V/T pots and switches. As you pull each piece of fishing line through the body holes mark it at the end where it went in at the pickup hole with a piece of tape so you know what V/T or switch hole it goes to. Tie the ends of the strings together where they come out of the respective holes. Run one for the jack also. Place any locking washers on the pots, switches and jack used. Tie the loose ends of the strings to the V/T pots, switches and jack that each one goes to as marked. Gently work the wired harness through the pickup hole and pull the strings. As you get each one through the body, cut the string about 8 or 10 inches from the shaft to hold on to. Put the string through the washer and nut that goes on the outside of the body, slide it down on to the shaft and tighten it up. All that is left is to solder the pickup wires to the pig tails. Use heat shrink tubing to prevent shorts from developing where the pickups are soldered to the pig tails. A paint removing heat gun or a high wattage (1800watts) hair dryer can be used to shrink the tubing with.

hope you dont have a Gibson 335, everything has to be done through the ‘F’ holes and pickup holes. you need a degree in patience.