Cell colours depending on value

I have a column of cells where each cell contains one of the following text values

Optimal
Normal
High-Normal
Mild
Moderate 
Severe

I would like the cell colour to be a set depending on what the value in the cell is. For Optimal I'd like a green and for Severe I'd like a red, and for the others I'd like a different colour in between. How do I do that?

Use Conditional Formatting - select Format, Conditional Formatting. In the window that appears, change the condition to Equals and type "Optimal" in the text box. From the list of styles (it says Default), select new style and format the text color to green. Create a new condition for each condition (Normal, High-Normal, Mild, Moderate, Severe).

PS: I may be slightly off since I don't have Excel at home.