Conditional formatting using text, not numbers, as the "trigger"?

Hello all. In a certain column of my spreadsheet, I want the background colour of the cells to go red if the cell reads “NO” and green if the cell reads “YES”.

How can I make this happen?

Use Cell value is with equal to and in the edit field enter "NO" including the quotation marks, choose or create a style with red background to apply. Then still for the same conditional formatting add a second condition Cell value is with equal to and enter "YES" and choose or create a style with green background to apply.

That’s exactly what I tried, but neglected to add the quotation marks. Thanks.