It's the same advice that they give to us parents that bring home a new baby!
Don't worry -- they'll get it together. We just also added Jett to the family on Thursday night. We got Jagger around Labor Day and my 14.5 yr. old Yorkie, Tyson, took it very well. Our house is insane right now with a 4 yr. old, a 9 month old, 2 pups and a "veteran" dog. But I love the chaos!