Conditional Formatting help

[Sarap75]

I have a spreadsheet that shows the employees who have masks assigned to them.
They are to have yearly annual services, I would like for those who are out of test date to show in red, those who are in test date in green and for it to change colour to amber when they are 1 month from being out of test date. I would like this to automatically update each year
Is there a way that I can get it to recognise the older dates and calculate with todays date to show the out of date one's and also the current in date ones? 
This is an example of how the spreadsheet is currently

393-394	17/10/2019	103898	JAVAID
395-396	09/11/2021	104615	LUCAS
397-398	16/10/2021	104214	MARSHALL
399-400	23/10/2018	104079	MURPHY
401-402	16/12/2020	104284	MILLS
403-404	19/07/2021	104230	WEBSTER
405-406	01/04/2021	104204	SARGESON

Thanks Sara 

[#2]

@Sarap75 

Use conditional formatting to highlight information

Conditional formatting can help make patterns and trends in your data more apparent. To use it, you create rules that determine the format of cells based on their values, such as the following monthly temperature data with cell colors tied to cell values.

How to highlight the dates over a year old in Excel?

none microsoft site

Maybe this will help you in your plans.

NikolinoDE

I know I don't know anything (Socrates)