Detector Building Questions

[Lily789]

Hi! This is my first year doing detector building, and I have a few questions about the event.

-My first question is whether teams have to build their own salt bridges or not? If we do have to build our own, what are some of your recommendations?
-For the event this year would it have to be a galvanic cell, or would it be possible to do an electrolytic cell? (Again what would you recommend)
-My partner and I are also a little confused about the purpose of the LED's?
-Lastly, any general advice about building a detector for this event would be welcome.

Thank you so much for all of your help!