Hey there people I have an issue that I have a problem with and I was wondering if anyone here could help.

My wife has been handed the task of putting together a training matrix for all of the nurses on their team, the idea behind this matrix is that it would show each individual set of skills that a nurse possesses and to highlight specifically when those skills will need updating. My idea would be to insert a date that the training took place and that the cell would highlight Green while the training is current, I would also like the Cell to highlight Amber when the training is coming close to its due date and highlight Red when it has expired. I have tried several formula that I have found on the web such as =NOW()+30 and =TODAY()+30 etc and setting colours for the various gaps that I would like...

I have three questions -

Firstly am I using the correct formula's for what I wish to do, and if not can anyone suggest an alternative?
Can the traffic light system work, as in can I set three different colours for for each cell that will change as a set date approaches?

Any further advice on this would be splendid. Thanks.