Solved Tutorial on how to target specific item (button etc) for styling

Hi - does anyone know of a tutorial showing how to do this - ie get a selector for a specific item on on page like a button for individual styling by using the browser's inspector. Or some other method.

I just can't seem to ever get this right!

Example - I can style a button custom in the regular UI but cannot seem to figure out how to change the rollover/hover state or select state for that button.

Thanks

 

OK - solved the button problem in Divi - was not aware of the hover state in the new builder.