All about search and rescue dogs
People often say they want to teach their dog to find lost kids and things. They notice that their dog loves to use its nose, and naturally think this would be a good thing to do. It is a great thought but often not practicable. Search and rescue is very rewarding, but it requires serious commitment on your part. You should count on training at least fifteen hours a week. Training includes being a "victim" as well as learning how to find one. That might mean spending hours hiding in some tick invested brush in the dark and wet. Training includes learning all the skills you will need to actually head out and find someone, map reading, compass skills, first responder aid (advanced first aid), radio skills and much more. You go out in all kinds of weather and conditions.
If this still sounds good to you then be prepared to prove your commitment. You will have to be persistent in order to locate someone willing to sponsor you. This system can be frustrating, but it does tend to eliminate people who have idealistic notions without the driving commitment necessary to bring a dog up to "mission ready" status. It is normal to take about two years to fully train a dog. And you will be paying for all your own equipment. Over a two-year period it is easily possible for this to get into the thousands of dollars (depends upon how much camping/outdoor/dog gear you've already got).