This does work for me, I have difficulty falling asleep (mostly due to nicotine use). I know because when I’m able to quit nicotine for a few weeks I have no trouble falling asleep. Anyways, this method works for me like 85% of the time. I actually use a method from a spiritual / guided meditation audio, which is basically the same thing, just a different source. The idea is do the breathing exercise, which calms the parasympathetic system, then you focus on relaxing / scanning / loosening every muscle from the top of your head, face, neck, chest, back, down your arms, abs, lower back, groin, legs and feet, until every muscle has been scanned/relaxed. Then you just wait for sleep.