How to replace the strings of an old guitar

First adjust the chords on the piano head, loosen the strings, and then pull out the nails. Use scissors or other tools to get stuck in the gap of the string nail, pry the string nail open, pull it down, and take off the string. When installing a new string, first put the end of the string in a little, fix it with a pin, pull the string out and press the pin in. When you hear a click, it means that the strings are installed. Then put the other end of the string in, leaving a length of about 5 cm, and cut off the extra part, and the string of the guitar will change.