Well, you’re doing it the right way round - cats don’t welcome canine newcomers to the home so readily.
Keep the kitty in a separate room, but one where the dog can smell and maybe hear him. Once the dog seems to be calm(er) about that (perhaps after a day or so), bring the kitten into the same room as the dog but inside a cage or carrier.
Allow the animals to get used to each other in this way for a couple of days, then take the kitten out and hold him out for the dog to sniff. If the dog seems calm, put the kitten on the floor and hold your dog by the collar so that he can’t get to the little feline. What you want is for the dog to lie down and watch the little guy explore.
Only when your dog seems calm in this situation should you let go of his collar. Monitor the two very carefully over the next hour or so, and be careful not to give the kitten more attention than the dog.
Good luck, and well done! :bravo: