here you can find out how to do it:
When stringing a new string, there are a few things you should keep in mind:

-If strings always break in the same place (e.g. at the top nut) you should take a closer look at the top nut. Do the strings run harmoniously in a curve through the grooves, or is there a kink? If the latter is the case, you should take the violin to your luthier. A kink creates a predetermined breaking point, the sensitive winding of the string will chafe here again and again until the string breaks.

-If the notches are okay, you can rub them with a soft pencil, then the strings will slide better.

-Next, check the notches on the bridge. If they are already very deep, this can damage the strings and also have a negative effect on the sound. In this case, you should also contact your luthier. If the notches are okay, you can also rub them with graphite.

-After you have unpacked the new string, wipe it carefully once with a soft cloth/dust cloth. Sometimes there is oil residue on the string, which can be removed in this way.

-Is the bridge straight? The surface facing the tailpiece should be at right angles to the violin top, and you can use this handle to pull the bridge back a little if necessary.

 

 

-Thread the string through the tailpiece and into the hole at the top of the peg. first wind over the end inwards and then outwards towards the pegbox wall. If possible, the string should not touch the pegbox wall.

-Carefully tune the string upwards, do not overtune it beyond the frequency you need. (A tuner or tuning app is recommended for beginners). Strings break if they are only slightly overtuned.

-Wait briefly and retune carefully once or twice. Strings give a little at the beginning.

-Check the position of the bridge again (see above)