I want to get him off of dog goodies and snacks like high protein chicken jerkey.

I would like to give my german shepard a different food, I was thinking canidae or innova, he currently has pedigree dog food. He has been eating this food for 2 weeks and I want to switch but how should I introduce the new food? Should I add a little of the new stuff to his current food and increase the amount gradually? By gradually that means how much per day? Sorry if this seems stupid but I am not sure and dont want to upset his tummy..thank you for serious answers…..what are your opinions on the canidae and innova? Sorry if I didnt spell them right but you know what I mean.
yes I know pedigree sucks but thats what I have for now so dont rip on me ok?