Automated colour fill based on dates PROBLEM

I need some assisstant with a problem it have at work. I have a column J named Resolution date and column M which is a indicater and column N closure date.

This is the way i need it to work.

If the closure date is four days or more over the resolution date i want column M box to turn red.

If the closure date is 1 to 3 days over i want column M to turn amber.

If the closure date is the same as the Resolution date i want it to be Green.

I Hope this makes sense.

If anyone could help me with this Problem i would appreciate it alot