There's a lot of things you can do, but it might turn out to be the easiest, least expensive to call the exterminator. You should price things out before you do anything.
Fleas go through a pupae stage during which they are enclosed in an extremely protective cocoon. It is critical that you make sure the fleas do not remain dormant and protected in that state throughout the duration of any treatments.
Inside the Home
On the Pet
Use a spot-on treatment which can be purchased in pet stores or from veterinarians or a systemic oral treatment which is available from veterinarians only.
Outside the Home
Sprays are only necessary outdoors if you detect lots of fleas.
Locate and remove debris in heavily infested areas, especially in areas where pets rest. Concentrate treatment in these areas with a spray containing a residual insecticide and the insect growth regulator pyriproxyfen. Open areas to sunlight by removing low hanging vegetation.
try some of these ideas: https://www.craftylittlegnome.com/kill-fleas-in-the-yard/
I would call an exterminator. They are wicked to get rid of. And might I suggest those seresto collars for your pet. They are the BEST things. They are around $60.00 but are good for 8 months so when you do the math they are a steal.
Borax. Sprinkle in carpet and around baseboards. I would reccomend Bravecto for your pet(s). My senior dog is allergic to fleas and I have found this to be best.