What you need:
1. a NEW set of strings.
2. a pair of string / wire cutters
3. about 20 minutes of your time
You should also determine whether your ukulele has a standard or tie-bar bridge and whether it has a standard or slotted head (see video) prior to starting your string-changing experience.
Loosen the strings on your ukulele by turning the tuning pegs. Depending on how the strings were last strung and the type of tuning pegs on your ukulele, you may have to experiment and see which way equals “loosen.” If the string pitch continues to get higher, you’re definitely NOT turning it in the “loosen” direction.
Once the strings are all fairly loose, you will reach a point where you can just pull the string off of the tuning peg. Do this for all of your strings.
Standard Bridge: Remove the opposite end of each string from the bridge of your ukulele. This may end up being a little tougher than you think, as strings sometimes get stuck in the bridge. If you’re having trouble, you may use tweezers or a pair of needle nose pliers to grip the knotted end – if you do be EXTREMELY careful not to scratch the top / face of your ukulele. Go on to Step #4*.
Tie-Bar Bridge: Grip the knot that is holding the string to the tie-bar and pull the free end of the string through the loop. If this is the first time you’re restringing one of these, it may look complicated down there now, but we’ll break down the knot, so don’t worry about forgetting what the formation looks like. Continue to Step #4*
*Note: At this point, collect all your old strings, wrap them around each other and throw them in the trash. This way, they are guaranteed to not be mixed in with the new strings once you take them out.
Standard Bridge: Take out your new pack of strings and remove the G string*. Tie a knot at the very end of the string, leaving about half an inch (about 1.5 cm) of string on one end of the knot. Pull the rest of the string towards the head of the ukulele and slip it through the hole in the metal pin of the first tuning peg.
Tie-Bar Bridge: Remove the G string* from your new pack of strings. Thread the string through the bridge from the side closest to the sound hole. Take the end of the string that just passed through the hole and loop it behind the end of string leading into the hole. Continue looping under the length of string that runs over the top of the tie-bar two times. Pull the free end of the string towards the head of the ukulele and slip it through the hole in the metal pin of the first tuning peg.
*Note: Strings are usually packaged in individual paper envelopes with their string name (for example, G) and numbered thickness on the outside of the envelope or noted on the string packaging.
Pull the string taut and set it into the first notch (reading left to right) in the nut. Start winding the tuning peg, to tighten the string. Typically, strings are wound “downward.” So as the string tightens, guide it to spiral downward, closer to the headstock.
Repeat Steps #4 and 5 for the rest of your new strings, in their proper bridge and tuning peg positions.
Tune your ukulele strings using your favorite tuning method. Remember, you’ll probably notice your ukulele going ‘off tune’ faster than normal for the first few days after re-stringing – this is normal, as the strings need time to grip and set in. It is fine to tune your ukulele a couple steps higher the first day after stringing to let them set, then re-tune them to normal tuning before playing.
You’ve now got your very own NEWLY STRUNG UKULELE!
Thanks to Ukulele Underground for this information