This site uses Simple-CMS and it works by inserting content i.e. text and pictures into a template. The page layout, colours, and all the technical stuff are defined in the template and the text you are reading is the content. If you look at the various pages on this site you will see that the content changes while the same template is used throughout.
Adding and maintaining the site content is REALLY easy: you just type your text into the Content Editor and for the most part, you write it in plain text and use intuitive techniques for formatting. For example, if you want a title you write the text and underline it. If you want a list you put has symbols (#) or asterisks (*) at the start of the lines; Simple-CMS then indents it and turns hashes into numbers asterisks into bullets. Special 'tags' can also be inserted into the text to display images (which are uploaded via Simple-CMS), link to other pages and other sites, and a number of other things. However the Content Editor guides you though this making it so that you really don't need any specialised knowledge to be able to change text, pictures, and other aspects of the content.
Admittedly, the templates are trickier because creation and maintenance requires a knowledge of XHTML and CSS. Consequently this is something that we handle for most of our clients... so not something you need worry about. :-)
Simple-CMS is designed to make it easy to achieve a good many things however there are many other things that it can't do. Were we to try to make it do everything its focus and ease of use would be lost. If you want guest books, forums, sound clips, or other complex functionality then Simple-CMS is probably not for you (although we have used third party software to add a simple shop mechanisms and galleries for some of our clients). If you have specific requirements, please contact us explaining what you want to do and we will endeavour to tell you whether it can be done with Simple-CMS.
Simple-CMS will allow YOU to create and maintain a web site that looks like it was created by a professional programmer and get your message across via the Internet. We feel we should warn you however that your competitors will not be happy about it and that your friends will most likely assume you're some kind of programming genius and start pestering you to do a site for them too. You have been warned. ;-)