What do I do when my flute doesn't make any noise?

The bird or block is likely out of place... adjust the leather tie and tighten the bird to the "nest" until you get the sound you need... This may need to be done each time you play.... or just once in a while. Temperature changes definitely affect the tightness of the leather holdfast...and you may have to tighten accordingly.

My flute jumps an octave or squeals when I'm playing... what is happening?

Sometimes the fingers aren't covering the holes completely and so their is a squeal or squeak.... or perhaps the bird or "block" needs tightening as above.