CSS is not easy for beginners to understand. If you don't know any HTML, well then you have a looong way to go. CSS saves you of a lot of time, especially if you're changing your front-page layout very often. CSS gives you the chance to change all the colors, fonts, links and much more with just editing only one code.
1. The first thing you need is of course a CSS code. If you haven`t one yet, then just copy this one.
2. Change colors and whatever you want to change. I have made some other CSS tutorials, so read them to understand more advanced.