This article has some good tips: https://www.cleanipedia.com/ph/in-the-home/how-to-get-rid-of-flies-fleas-and-mosquitoes.html
Hi this is Peggy. Sorry you have fleas and flies. Be sure not to leave any food out on your counters or dirty dishes in the sink. If you have pets be sure to take them to the vet and get the medication for fleas. Vacuum daily and take the remains from your sweeper outside. It will take time, but if you keep after the problem it will go away. Good luck. Please do not use the flea collars or the cheap drops you buy at the store, they are harmful to animals. About 28,600,000 results (0.81 seconds)
Vinegar and dish soap fly trap
How to Get Rid of Flies Indoors | Ehrlich Pest Control About 28,600,000 results (0.81 seconds)
Here's a DIY flea treatment that might help
Pennyroyal plants are effective to deter fleas. Basil, planted en masse will deter flies. Indoors, cleanliness is the key. Scrub out all garbage cans with bleach water. Scrub out all cabinet interiors, walls and floors. Check hood vent screens for grease. Pull out your stove and refrigerator and clean behind them.
Indure windows are tight fitting and screens have no gaps.
Hose down your patio surfaces with Dawn liquid in warm water. Wash exterior window and door sills with soapy water.