2 male dogs

Question
how do I get my older male boxer to like my new male english mastif puppie

Answer
How old is the Boxer?  Once past 3 years old, many dogs don't want anything to do with puppies, their sharp little teeth, and their biting games.  You need to teach the puppy to leave the older dog alone.  As soon as the puppy starts to focus on the older dog, give it a sharp ''Ah, ah, ah!'' and offer it a chew toy.