How should it fit? Should it be tight and not move?
It shouldn't be overly tight, it is designed so that you should be able to feel the vibrations even if it isn't flush with your wrist. Some movement on your wrist is expected!
When the measurement specifies dimensions, is it referring to the distance around the bracelet or the distance from one side to the other regarding width? Thank you!
The dimensions measurement is the distance around the bracelet (circumference).