I've got a silly question.

Folks have tried to explain this to me before but my thick skull can not comprehend. Could some one please explain....

How do I attach a bobber stop on my line and how do they work.??Please explain as you were talking to a 5 year old.Serious.

Reason being. My friend had his bobber at 9 feet the other day and had a hog of a speck on. Needless to say the bobber was jammed because he double clipped it and his 20.00 speck swam away. Our local tackle shop pays 20. bi weekly for the biggest speck caught.