– crossed‑out “loose jacket” with head submerged face‑up.
If you must jump into the water while wearing your lifejacket: Keep your feet together and legs slightly bent . eval lifejacket donning instructions
Grab the waist belt (usually a 25mm or 50mm webbing strap with a quick-release buckle). Bring the two halves together around your lower ribs/upper waist. and pull the free end of the strap to tighten firmly. You should be able to fit a flat hand between the strap and your body, but no more. but no more.