So, you wanna learn SSI(Server Side Included)? It's actually pretty easy!
Okay, first, you should make 2 new text files called top.txt and bottom.txt, or whatever you want to call them.
Next, you want to put the top part of your HTML into top.txt. By the 'top part' I mean the layout that is going to be on every page of your site you want it to be. So, you should Cut and Paste the layout that goes right before your layout into top.txt. Then, do the same thing with the bottom part of your page, after the content. Cut and Paste it into bottom.txt. Then use this code on the top part of your page, before the content:
Then put this code into the bottom part of your page, after the content:
And last but not least, you must label all of your webpages ".shtm" or ".shtml".
Oh, and one more thing, your host must support SSI! (duh). In order to make a .shtml or .shtm page (if your host doesn't automatically have .shtm or .shtml as a choice when making a new page) you must rename the page as pagename.shtml or pagename.shtm.
Note: If you use FreeWebs you don't need to rename the site.
Got all that? If you did, then you know SSI!