I usually start my pups on mushed/watery dry puppy food at about 4 weeks old... I soak the puppy food in water (not much food...).... then when the food expands I mush it up.... keeping most of the water with it.... This just gets them started in learning to lap (don't fret if they don't go for it)... I do this everyday (at least once a day... sometimes more).... By week 5 the food is still soaked but I don't leave the water... they just get mushy puppy food.
By 6 weeks they are usually eating on their own... and also eating from "mom's" dry food.
I did have one litter which refused the mushed dry food.... I started them on canned puppy food during week 5 (picky, picky, picky).
By 6 weeks they are all weaned from mom.
Good luck!!!