If it were me, I just wouldn't do it. I'm not saying this to be discouraging, but just from my own experience...
We got our cat, Gus, from a friend. Poor Gus- the reason he came to live with us was because--although he'd lived in a house with four cats and two smaller dogs, the owner had moved in with her boyfriend who had two larger dogs. So, when they asked us to take Gus, he was living under the bed. In fear.
When we got him, we noticed that he wasn't eating much. We took him to the vet and the truth came to light-- he hadn't been eating for quite a while. Weeks, likely. In fact, because of his feline anorexia, he ended up having feline fatty liver disease,which we fortunately caught before his pancreas was damaged. He spent three nights at the vets and after we brought him home, we had to tube feed him for a month. The vet bill was around $2,800 (which we got financing for, thankfully).
Poor Gus had to learn to trust us the hard way. Fortunately, he's still with us and is now 16 years old and quite the older gentleman kitty.
My advice to you would be to wait until your cats have lived their lives, and then get a dog. Cats aren't like children, who can somewhat understand when a new sibling comes along. And if this dog is in the habit of chasing cats, it's likely really going to freak your cats out. They simply don't understand that this new animal is going to be a 'friend'. I think it works better when either the cats are kittens or the dog is a puppy.
I see others have given you advice which might very well work. Nonetheless, it would be worthwhile to keep in mind the idea of having a plan B., so that if the cats and dog don't grow to be fond of each other, you have other options. I just know from my experience with Gus (and we won't even get another cat until he is no longer with us), it can be dicey.