It can take time with some. Just try to keep your "pre" new puppy, routine as close to the same as you can. REasurre Walker, make a concerted effort to pay as much and more attention to Walker as the new puppy. Don't try to force the relationship. Let them feel each other out, if the puppy annoys Walker, keep them seperate. Let Walker go to the puppy. Let your new puppy learn potty behavior from Walker, when you take him out, take the puppy out too.
With patience and fairness, you'll get through this warming up period
Also, don't leave them alone together when you leave, always supervise when they are together, initally.
It won't be long before you will see a connection, or event or moment when you realize they are going to get along just fine
