How to write an If Function

Hello,

I have a spreadsheet that shows how many days a requisition has been open. I would like the words GREEN, YELLOW, and RED to show up in a cell if the req has been open a certain number of days and have no idea how to write that formula out.

So if the req is open less than 30 days then the word GREEN would show up in the cell next to it. If it is open more than 30 days and less than 60 days then YELLOW would show up, and if it is open more than 60 days then RED shows up in the cell next to the number days.

Any help will greatly be appreciated!!

Thank you!

Randy