Thank you Aileen for your question. This is an often asked question and a lot of misconceptions do surround puppy training.
Basically, the day your puppy was born it started to learn. It learns life lessons early via its Mum and its siblings. From therein, it never stops learning.
Dogs absolutely love learning new things and are capable of learning many new skills from the minute you get them (hopefully though only after 8+ weeks from birth). The only thing that we need to ensure is that we don’t involve our new pup in physically demanding activities (such as agility etc) and that it is allowed to take plenty of rest/sleep breaks. Sleep is vital for puppies as a lot of their growing happens whilst they sleep.
If you start training your puppy from the minute you get it then not only will you be solidifying the bond between you and the pup but it will also be learning rules and boundaries from you. This means that it will be less likely to look to make it’s own life rules when it hits the 6+ month mark (often viewed as it’s pubescent/teenage temperament stage) and should look to you, by default, as the provider of security, sustenance and all the good things in life such as play and games. Training, to a dog, is just game playing and should be a joyful experience to both you and your pup and become a lifelong commitment.
Remember you reap what you sow therefore the earlier you start the better and the positive engagements will become embedded in your pup and thus form an integral part of it’s own internal life rules. In addition games and other positive interactions will also manage your pup’s energies and build its confidence which, again, is vital when it has to deal with new issues in the future.
I hope this helps. Good luck.