How to Color a Cell Based on the Cell's Value

I am an educator and use Excel to keep and calculate student grades. I would like to automatically flag students who are doing poorly in some aspect of their grade. For instance, if a cell value is below 60%, I would like to turn the cell red, but I don't know how to do that. Any advice?

Take a look at this site for numerous examples of how to use Conditional Formatting:

https://www.contextures.com/xlCondFormat01.html

Perfect! You're a genius!