@miryam9 the base strings need to be the length of the bracelet + what you need for the ties or loop etc. and for the leading strings I recommend to leave them on the skein and cut them in the end.
@Dwarfboard Kinsey B has a tutorial where she actually uses this pattern. It’s mainly for how to do triangle ends and an alpha, but she briefly explains the loop. I can’t put links in comments, but if you search up how to make triangle ends on alphas Kinsey b, it should come up.