SSI stands for Server Side Includes, which helps you to make pages easier instead of going to each page and adding your layout would take forever, but with SSI you would just edit one or two pages. There is two versions of SSI the HTML way and the PHP way below i will explain both.
First you have to make 2 different files name the first one upper.txt and the second lower.txt.
Your upper.txt file includes CSS, left nav, and Banner. Your lower.txt file includes your Right Nav and Disclaimer, Add these 2 codes in the order i put them.
So there you have it that's the HTML Tutorial.
Follow the steps above when making the upper and lower.txt files, but this time the code changes. Use the codes below when making a page.
If you are still having trouble E-mail me Chimchar Master and i will help you.