The Swing brings the mucus from the lungs by centrifugal force and an otherwise non breathing baby can then breath through cleared lungs.
The back is supported with the back-swing so as not to break neck or back.. just couple swings should do the trick.. then lay baby down and Re-clear mouth and nose.. If still not breathing...repeat the Swing.
Much more effective than Mouth to Mouth as the baby's lungs are so tiny..it is easy to pop the lungs with just a puff of breath from you..
Hope this helps to better understand how to Swing the baby..has saved many of mine in the past..hope it can be of help to you too
Here is the famous "Swing Baby" nearly 3 years later..
She is an absolute delight to my herd.. and Oh! sooo cute!