I have created a drop down list using data validation. What I need to do now
is have cells filled out based on the value selected.

In this case, the list has three values (Cell A1), and I need to have a
range of cells (C7 to C54) populate data based on the specific value in A1.
The other data is on a sheet named "Data Entry."

Is this enough information or would I need to provide more?