Start off with a ton of research.
I don't do puppies, so I can't tell you how to start. There are books, forums, and ton of sites to research for what's best for your situation. If it were me, I'd likely start off with a premade raw. Natures Variety, something along those lines.
Benefits... too many to name. But for starters, if you do PMR when the milk teeth fall out then they'll likely never need a dental. Skin and coat are healthier then most, less likely to have food allergies, boosted immune system, less poop, and less likely to have to clean up said poop. Moisture intake is significantly more then kibble fed dogs, and so renal issues are almost unheard of. The list is long on the benefits side.
Cons... meal prep is time consuming, finding a fair price and keeping variety is a pain in the butt, and you need a freezer dedicated to dog food.
"i can explain it to you, but i can't understand it for you."