We lived on our ten acres, usually with a pheasant somewhere on it, plus the chickens we raised and the bantams that ran loose and had two boys, one of preschool age, when we got our springer pup. The pup came from a place that also had acreage, with bantams runing loose. Thus, I think you could say he was country pup, from day one, which I think gave him a great advantage in life.
At two and three months old we would walk him around where pheasandts had been. He soon became interested and could detect a pheasant track when he came across it.
We had a game we played, which also taught him and which anybody living in a city could also do. I collected a bunch of pheasant feathers and tied them onto a sponge like ball of material. The two kids and I would go into the basement in the evening. The boys would hold the pup and cover his eyes, while I dragged the ball of feathers around the floor, in and out of rooms, then hide it. We would show the pup my starting point, then let him go. He would follow the scent track of the pheasant feather ball all around, until he found it, then come bounding back, for his praise, petting and treat.
When the pup was six months old I took him hunting, with a friend who had an experienced lab. The lab got onto a bird in thick growth of waste weeds and grass. The lab gave up, the other hunter walked away, I put the young springer after it and he flushed an old, cagey ####!
I don't think you will find my game method of training in any book, but it worked! That springer became a tremendously good pheasant dog, as well as a duck retriever, able to go by hand signs anywhere I asked him to go on a duck pond, to retrieve a duck he didn't see.