So, you now have a dog and a new kitten! Congratulations! Remember to be patient and take things very slowly.
Before getting your new kitten, you have made sure that Fido likes other animals and does not view smaller animals as prey and that he is ready to have a pal of his own.
When you bring kitty into the house, be sure to have one room that he can feel secure. Let Fido and Felix sniff each other from under the door and play footsies for a few days before you even think of putting them together. Praise your dog for not being aggressive with the new kitten and give him treats and lots of attention by himself so he does not feel threatened.
Once you are confident that they can meet, (you can tell by the lack of hissing from kitty that he may be ready to meet his new friend) then have them come together with you as the supervisor. Sometimes it takes several days and other times it takes several weeks. Do not rush their progress. You will be able to tell when they are comfortable. When introducing, leave the door to the room open so that your kitten can run in there and feel safe if he ever feels threatened. Kittens usually adjust fairly quickly and love to explore their surroundings once they are comfortable.
You will eventually find if it is going to plan, your dog will start ignoring the kitten. That is usually when you can allow the kitten to run around and explore the rest of the house.
Soon, your fur kids will be fast friends!