https://deployedmedicine.com/ is a fantastic free resource. This is the official site of the U.S. military’s TCCC (tactical combat casualty care) training. The Level 1 / All Service Member course is a good start for most rational preppers. Lots of pocket guides, curriculum, and videos, etc. All U.S. military service branches are transitioning to this curriculum, born out of the lessons learned in Iraq, Afghanistan, etc.