scoffey, it depends upon which D-Worm product you used for the puppies and how seriously infected they are. You should follow the dosing instruction that came with the product. In case, for whatever reason, you misplaced the instructions, Farnum is the manufacturer of D-Worm. Here is a link to their webpage which lists each product. Click on the link of the product you have used. Directions for use is included:
Farnam Pet › Products › Search Results
Check your puppies stools regularly. It will take a few days for the dead worms to work their way through completely. Make sure that the worms aren't moving around. Keep checking the stool. If after a few weeks, there doesn't appear to be any worms, the one dosage should have done the trick.
Please speak to your vet about the different flea treatment options available to you for puppies. If you don't get the fleas under control, you will continue to have problems with worms. Fleas are worm carriers and all you pups have to do ingest one when chewing on themselves for relief. Since you didn't mention their ages, I am hesitant to suggest anything. But, the safest products are sold through the vets offices, not over the counter.
Just as an FYI, tapeworms can also be transmitted through a dog managing to catch and eat small animals, rabbits specifically. I doubt very much your pups ate one, lol, but store that info away.