If you found kittens, evaluate the situation before jumping in. If possible watch the kitten/s and see if the mom cat comes back. Most mother cats return to the kittens after hunting for food, or finding a new, more secure location. Mom cats will move the babies one at a time. Kittens are less likely to survive without mom.
Did Mom cat return? If so, leave the kittens alone with the mom until the kittens are weaned. You should offer mom cat food, clean water.
If Mom did not return and the kittens are older then 8 weeks old, you can get them spayed/Neutered. If they are younger then 8 weeks old, they will need to be fostered and possibly bottle fed. Kittens that have never been around humans need to be socialized. If kittens are older and have never had human interactions it could be difficult to socialize them.