Don't do that !!!
My Lily had pups 5 weeks ago, this is her first litter and my 4th
I have bred and raised.
Yes start puppy food, only seperate the mom and pups when the pups are eating.
Your mommy dog should wean them on her own. She will too, especially when they start biting with their teeth. When the pups are about 7 - 8 weeks you will notice the mommy dog will lessen her time with the pups.
Her milk should dry up naturally also.
I'm sure she is doing it right now. Does she sleep with the pups?
My Lily stoppped that 2 weeks ago. But she feeds them regularly
Never seperate a mommy dog for more than a few minutes if possible.
With the puppy food, I use Nutro: Lamb & Rice Puppy Food.
I water it down to make a paste or pablum, this gives the pups something soft to swallow. Remember they need to learn to chew.
So first the musshy food and gradually with in a week for your guys, they should be able to chew dry Nutro kibble.
I normally start pups at 4 weeks the pablum, lessening the water within a few weeks. So by 6 - 7 weeks they eat dry kibble.
Good luck