Find a local club, attend a training session to watch them as they work their dogs, attend local events and IPO competitions, and talk to people involved in the sport in your area. Eventually, you'll bring your dog to be evaluated with a local IPO club and they can help you figure out where to go from there. Books, videos, etc are nice but real experience with clubs is the very best option for someone looking to get into the sport.
You can technically start any time, clubs usually do drive building and grip building with super young puppies... they stop during teething, and resume rag and tug work when a puppy's adult teeth are in.
Protection usually doesn't start until much later when a puppy is older, after they have a solid foundation in obedience. I started with my male around 1 year of age. Depends on the club and the dog as an individual, too.
SG S-Hunter vom Geistwasser CA CGN TT (Airport Wildlife Control K9)
Zenna vom Geistwasser
"May my enemies live long so they can see me progress."