CSS non Table center with comments

I have an html file that I am using CSS to create a two column centered with a header and nav on top of the twp columns. I need the file commented so I can know how you did it. This is for one of my classes so it's important that you explain the process so I can learn from it. I created a nav bar using CSS I also need that commented so I know how to recreate it. example of what I mean background:white; /*This will set the backgound white*/ it should take 5-10 minutes. I am stuck since I am a newbie learning this. Please downloaded attached file that has the html file you need to comment and center ## Deliverables 1) Complete and fully-functional working program(s) in executable form as well as complete source code of all work done. 2) Deliverables must be in ready-to-run condition, as follows (depending on the nature of the deliverables): a) For web sites or other server-side deliverables intended to only ever exist in one place in the Buyer's environment--Deliverables must be installed by the Seller in ready-to-run condition in the Buyer's environment. b) For all others including desktop software or software the buyer intends to distribute: A software installation package that will install the software in ready-to-run condition on the platform(s) specified in this bid request. 3) All deliverables will be considered "work made for hire" under U.S. Copyright law. Buyer will receive exclusive and complete copyrights to all work purchased. (No GPL, GNU, 3rd party components, etc. unless all copyright ramifications are explained AND AGREED TO by the buyer on the site per the coder's Seller Legal Agreement). ## Platform Windows Explorer, Netscape, Firefox