It is a lot easier (for me, in some situations) to create a gif showing how to implement a solution (instead of writing it up in a list, like: 1. do this, 2. do this, ... 14. do this).
Consider the following answer (which is short, so not the best example): Is the gif on the bottom of this post appropriate as a replacement for the instructions?
(I would imagine that Stack Exchange might not want such answers, as they are not searchable by both this website, and search engines like Google.)
Use this formula:
- Select all the cells that you want to have the rule
- Click on New Rule under Conditional Formatting
- Enter the formula in the formula box (see screenshot)
PS. I am surprised that I haven't been able to find a similar question, please let me know if there is a duplicate.