You need advice from professionals, not strangers on the internet. Start with a google search to get general information.
You need an actual insecticide to kill fleas. Normally you would use a liquid flea killer to bathe the dog, then you put that liquid in a lawn sprayer and spray your lawn with it. Also spray over the fence into your neighbor's lawn. Then you use a powder to kill the eggs, and if you allow the dog inside you will need to work that powder into your carpets and furniture.
A professional will tell you a lot more advice like this, and then you will be free of fleas.