A puppy is a lot of fun but also a lot of work. Especially in the first months, training should be started to make his place in the family *pack* clear.
The training takes place lovingly but consistently. The puppy/young dog should learn to cope with obedience, environmental stimuli, conspecifics, other animals and people.
The younger your dog, the shorter the training sessions. Training blocks of 10 to 15 minutes are interspersed with relaxed minutes of play to release the tension from you and your dog.