What the best way to do it with a 5 month old pup , the waterdog book said to start start when they are young.

I conditioned Sadie at a skeet range... I took her with me and we waited in the car for a bit. The guns got her excited yet nervous at first. I got out of the car and eventually she wanted to get out. Then started sniffing and on the leash I slowly worked her over to the sitting area and she hung out all day watching.

I started sitting tank about 40 yards away then shot away from him, then let him sniff hull and praising him. I kept working closer until I was right next to him. Threw the bumper a few times between shots. I shot probably 5-8 times.

Start off with someone else shooting at a distance while you stay w/ your pup. I will pet the pup while gun is shot to distract as well as comfort them. When they look toward the shot the shooter throws a dummy. I let the dog get it & we will throw a few fun bumpers then repeat the shot scenario. The pup associates the shot to something falling & going to fetch it. 3-5 shots a day to start off & in a few days you can shoot & throw the bumper w/ the pup at heel.
As w/ any aspect of training, there is no magic formula. Watch & read your pup. If they nervous or scared you better back off quick. If the enthusiasm is up & tail is wagging, carry on & always end on a positive & hopefully w/ them wanting more.

Ive always started mine off at a couple months old when I start taking them in the boat evey time I go. Always take a 22 and shoot chit while Im out there. By the time I start gun training with the dog its not an issue at all. But its like anything else, if you get them excited about any drill they will like doing it.

I used to buy five or six quail and clip the fight feathers off one wing. Pump the dog up with the bird then throw it. Just as the dog is about to catch the bird, shoot a 22 or shotgun primer behind your back. The dog is so jazzed about catching the bird, it won't notice the bang. By the sixth bird, you can touch off a cannon and the dog won't care.