Flea comb and a dish of soapy water. Get the fleas out with the comb and drop the fleas in the soapy water. (They sink to the bottom). Try not to have bubbles in it as they can climb on them and jump out.
You’ll also want to vacuum and toss the bag or empty the canister outside when you’re done. Flea eggs are a drag. Once she’s old enough you can get drops or something that kill fleas when they get on her and it’ll be smooth sailing after that.