When a child is breathing normally but is unresponsive/unconscious, and if injuries allow, the next procedure would be to place them into the recovery position, injured side down. This can be achieved even when the child is on their front or side.
If the medical services take longer than 30 minutes and if injuries permit, turn them onto their opposite side.
Here is a video and guide on how to place a child into the recovery position
Video courtesy of CPR KiDS