Buy yourself an EMT textbook. The actual course may be overkill for what you want to do, but the book would be good basic learning and reference. Basic first aid courses will teach you the some of the basics, an EMT course will teach you confidence and practice in doing those basics, and moving up to EMT-I (if they have that in your area) or Paramedic beyond that add more advanced skills - most of which are invasive, or drug therapy, or use specialized/expensive equipment you won't have laying around the house (defibrillators, laryngascopes, etc.) You also would need a physician advisor to work at the Paramedic level (at least in my state).