Danica Liebold

I have a 50 pound 9 m old puppy and will be getting a 6 pound 10 week old puppy in couple of weeks and am concerned about larger dog playing to rough or sitting, laying on her. How do I train larger pup to be easy with her. I have another older small dog that keeps him in line and 2 cats that let him rough house with them and they keep initiating the play but don’t want new smallest puppy to get run over.