my go to place is Leerburg.com they have super articles and free videos as well as great DVDs to purchase/stream. Give him lots of time, even months, to really bond and get into your habits and ways of doing things. His entire life has changed. And for the better, but they don't realize that. And if he had no rules before, it will take longer for him to learn yours. Read about introducing dogs into your house and pack structure. Very important. Keep them apart for now and read and watch Leerburg's videos and articles as you only have one chance to do this right. I did it wrong with 2 spayed female GSDs and never could have them together.
dogbyte Cathy, Rossi ( the Dutch shepherd) and Gunny (the Czech/DDR GSD) with Zoey, Chance,Xara,Gracie, and Jaden snuggled deep within my heart