Mom will show them the food and water! At first I sprinkled some food on the floor near the nest for them as they were so little and clumsy and scared, but it was probably unnecessary. Just make sure whatever container the food and water is in that the ducklings can easily access it. I gave mine a separate small/low sided feed/water dish near the nest and left the regular setup for the big girls out in the run. After about a week or two when mama wanted to take them out and about more and they were a bit more coordinated, they all would just eat/drink together outdoors.