A dog is never too young to be trained properly. Start with leash training and to do so begins with fitting the pup with a collar. Make sure that it fits loosely so that the puppy can move its neck freely. A too-tight collar will make the pup uncomfortable and will therefore run away when it sees a collar the next time you try to put it on. Release the pup, and let it get used to the collar’s weight.
After a while, you may then attach the leash. Don’t lead the pup just yet. Carry it outside and set it down. Try to make it walk a step. If it puts its behind on the ground and refuses to budge, a little bribery will help. Give the pup doggie treats and lavish him with praises when it follows. If not, don’t drag the pup. Give the leash a tug then release. Call the pup. Repeat this a few times until it finally budges.
A few minutes a day is enough, as it will eventually learn what a leash is for. By that time, the puppy will walk beside you and not pull with the leash. Don’t forget that patience is a virtue, and this principle applies to teaching your dog new tricks.