First of all, the kittens shouldn't be weaned before they are 8 weeks, if possible. 3 weeks is way too soon.

Keep them isolated to one room with mama, for their own safety and well being. Let them have peace and quiet. At 6 weeks, you can begin weaning with a saucer of canned kitten food mixed with KMR, a milk supplement in a can. Put a little on your finger and put it to the kitten's mouth to lick. Put their mouths to the stuff and they'll get the idea.

Unless you plan on keeping them all, I'd keep them isolated. Especially since none of them have had their shots yet, and also if there are any other pets in the home.

If you plan on keeping them and there are other pets, you will need to be introduced gradually.