After typing the error message in the Data Validation dialog, what is the next step?

After typing the error message in the Data Validation dialog, the next step is to click the OK button. This action confirms the settings you have configured, including any changes made to the error message and validation criteria. By clicking OK, you are finalizing the data validation settings, which will then be applied to the selected cells.

It's essential to click OK to ensure that the validation rules and the customized error message are saved and activated. This will prevent users from entering incorrect data in the validated cells and display the specific error message you created if they do attempt to enter invalid input. Other options like Cancel would discard the changes, while Apply and Save do not specifically pertain to finalizing the dialog in this context, making OK the appropriate choice to confirm your entries.