welcome to YT and congrats on ur little baby, 6 weeks is VERY young, whats his weight and why did this breeder let u take him home?
This is  BIG responsebility, u could mix his dry food with a bit of boiled water to make them soft and add some wet puppy food i would also mix his milk with the dry food and feed him every few hours. make sure he drinks and keep nutrical on hand incase he gets lethargic on u, these young tiny babies crash easly and need 24/7 care!
DONT bath him for the next few weeks!!
Let ur vet check him out properly. 
Good luck 
