I have puppies that are not even 24hrs old yet. I have found fleas on them. How can I treat them without hurting them?

Fleas on puppies can be very dangerous, it can quickly lead to anemia and death.
Get a small tub of warm water, not too hot, just luke warm and put some dish soap in it. Have another tub of clean warm water next to it.
Gently wash the puppies one by one in the water/soap mix and rinse in the clean water.

Dry them VERY thoroughly and get them back to mom as quick as possible. Do all this right next to the whelping box so mom can see what's going on.
It is important to make sure the puppies are dry before returning them as until they are 2 weeks old they are incapable of regulating body temperature so can easily die from the cold.

Fleas can survive in regular water, but not in dish soap, it coats them and drowns them. You will wanted to follow this up with a flea comb as well.
Repeat every week as this only kills the fleas, not the eggs.

Talk to your vet about flea treatments for mom because whatever you use on her will be transferred to the pups and they are too young to handle any sort of flea treatment besides the dish soap.

If the pups have fleas I am assuming the mom does as well, and treating the pups without treating mom will just get you back to the beginning. Talk to the vet about treating the mom and pups, they may be able to give you something that is safe for the pups and mom.