to change a string
loosen the string so it is quite slack
using a rubber/eraser as a fulcrum lift the bridge pin up out of its hole with pliers
Pull out the string.
Tie a new string to the end of the old one and pull it up through the neck using the old string
then remove the old string from the tuning key shaft and insert the new string through the hole in the tuning key and tie a triple knot to stop it slipping back through the hole

The string is held in the soundboard as shown in the diagram at left
place a small bead on the end of the string and tie a triple knot on the end of the string and pull the knot tight
push the end of the string with bead into the hole and insert the pin as shown with the groove in the pin facing up the soundboard . The string should fit in the groove as the pin is pushed into the hole
wind up the string making sure it is not caught on other strings and it winds neatly around the tuner shaft
Bass/wound strings are similar except they have a thick washer at the soundboard end and are installed via the sound hole in the bottom of the soundbox