How Much And How Often Should I Feed My 12 Week Old Staff?

How lucky you are to have a puppy of this wonderful breed! The way to feed your faithful friend for life, is to get him into a routine early. He should be given breakfast when you wake up, this is normally when he will learn to go out for a wee. It will be his morning routine.
Give him balanced cubes and plenty of water, try not to give him meat and cubes, because the protein content will be too high. Try not to feed him titbits.
Then at lunch you can give him half the amount  he had at breakfast, about a cup.
He will want to chew, you can give him a sinew bone thats big enough to not chew up in a day and swallow. It may save some shoes and slippers, these pups love to chew.
In the evening after a walk, another routine he will learn and use as toilet time, you can give him the same portion as breakfast. Eventually the lunch feed will fall away and he will eat morning less and dinner main meal of the day.
Some people give their puppies milk, but it causes mucus, and really they are having  balanced food.
Be sure to buy the best you can, in a packet, don't skimp and buy cheap tinned food.
Always make sure he has water. You can also make a vegetable broth to go over his cubes.
Give him a kiss from me.