I am quite new on CMS's and stuff, so please bear with me.

I arranged a tricolumnar view.
I would like to have separate "modules" on the side columns. That is, the left and the right columns should be somehow split in two or more "boxes" each. On one or more of these boxes I would like to place fixed articles.
As an example one of my articles should be composed of, say, a disclaimer for the site or a list of programs I have installed on my machine (just an example). I would like this to be an article and not a fixed part of the column, to ease updating and replacing it at a later time.
What should I do to accomplish all this?
Thank you for your attention.