Your pup needs to be obedience trained before you formally start training it for hunting. You need to be able to control it at home before you take it afield. If it don't come back to you at home each and every time you call it, it will be long gone once it hits the woods......believe me. Tip....a dog's name is not a "come" command. It is only to get their attention.
That said, introducing your pup to hunting informally can start anytime. Playing find and fetch games in the back yard using scents from the game you intend to hunt will familiarize you dog to what you want of him. It is also a good time to introduce hunting commands such as "go find", "give" and hand signals. But keep it play and keep it short. When your pup becomes disinterested, it's time to stop. Take your pup to the woods....on a check cord if you don't trust it. Introduce it to different situations and riding in the car/truck. You want it to associate the rides to fun. You need to train it how to ride under control in the car/truck without the stress or excitement of the hunt involved. At six months or so one can formally start more intense training, but again keep it short and fun for the dog. Losing your temper or forcing a dog at a young age can create bad habits that can take months if ever at all to undo. Before using any kind of shock collar, your dog MUST be obedience trained and completely understand what you are asking of it.
Good luck and have fun with your new pup.