Sometimes it takes a while for the hormones and motherly instincts to kick in. If she is allowing them to nurse, she should take over the rest of her duties shortly. If not, then you'll need to stay with her and encourage her. Put a bit of butter on the babies' butts and that might get mom to clean the little ones. Be sure that she doesn't hurt them by snapping at them. I slept with a new mom and singleton for a week with my hand in the box. We tried everything those first days bec' she wouldn't go near him. My vet even suggested giving her a mild tranquilizer, which we did. It didn't help. She ended up being a great mom. It just took a few more days than usual. What is your new mother doing that concerns you? How many babies? Has her milk come in?
I have a litter of 2 week old pups from a first time mom. When the 1st pup was born and started to nurse, she kind of growled under her breath. She never snapped at them. She has a small litter of 4 pups, and is not overwelmed. She quickly became a concerned and loving mother.
What is she doing that you are concerned about? Did she have a c-section or deliver naturally? Give it a few days, they usually get the hang of it. You just need to monitor her closely during this transition period.