"CMS" stands for "Content Management System." A more descriptive term would be, "Website That Is Easy to Update and Manage Instead of a Huge Hassle," but that's a little long. The goal of a good CMS is to make it painless, even a little fun, to add and manage the content on your website. No matter which CMS you choose, it's extremely helpful to understand a few basics about how they work.
Think About Content, Not "Pages"
When we "browse" the Internet, we generally think of ourselves as moving from "page" to "page". Each time the screen reloads, we're on a new "page."
This analogy to books has some good points, but you'll have to drop it if you want to wrap your head around making a website. Books and websites are incredibly different technologies.
In most books, almost everything on each page is unique. The only repeating elements are the header and the footer. Everything else is the content. "Writing a book" ultimately means assembling a single stream of words that will start on page 1 and end at the back cover.
A website has a header and footer too, but think about all the other elements: menus, sidebars, article listings, more.
These elements are separate from the content. Imagine if you had to recreate the menu separately on every page!
Instead, a CMS lets you focus on making new content. You write your article, you upload it to your site, and the CMS spits out a nice page: your article plus the menus, sidebars, and all the fixings.
Make Many Paths to Your Content
In books, each chunk of words basically appears once. Most of the time, you start at page 1 and read to the end. This is a good thing. No website, or even ebook reader, can offer the chance for deep, sustained concentration you get when you hold a single physical book in your hands. That's what books are good at.
With that goal in mind, most books don't need to offer many paths to the same content. You have a table of contents, and sometimes an index. Maybe some cross-references. But most people are going to read the whole book, so these aren't the focus.
Websites, however, usually feature articles or even shorter snippets of content that can be read in any order. A blog may be written in chronological order, but visitors will land on any random post.
So it's not enough to post your content. You need to offer many ways for visitors to find what they want. This can include:
listings of recent article titles, sometimes with teasers or blurbs introducing the article
category or tag listings
listings of similar or related articles
syndication: an RSS or Atom feed, for readers who use a feed aggregator
an archive by date, in case anyone's feeling sequential
maybe even an automated email newsletter
Every time you post, all of those things need to be updated. Can you imagine doing it by hand?
I've tried. It's not pretty.
And here's where a good CMS really shines. You upload your new article, add a few tags, and the CMS handles the rest. Instantly, your new article appears on all those listings, and your RSS feed gets updated. Some CMSs even notify search engines about your new piece. All you have to do is post the article.
A Good CMS Makes Life Easy, But You Do Have to Learn a Little
I hope you have a sense of all the complex, tedious tasks a CMS tries to save you from doing. (And I haven't even mentioned letting people leave comments.) A CMS is an astounding labor-saving device.
However, you do still have to learn a little in order to use one. If you're managing it yourself, you may have to learn a few arcane rites to get it installed.
Many web hosts offer one-click installers. Eventually, though, you'll want to make a copy of your site so you can test new designs and upgrades. You may have to learn the manual installation anyway.
You'll have to learn about software upgrades. The developers keep adding improvements and fixing security holes in the code, so you need to keep your copy current. If you don't, your site will eventually get defaced by some automated script.
A good CMS makes upgrades relatively easy, but you still need to do them. Sometimes, you need to test the upgrades on a private copy of your site first. And you have to be careful not to make any changes that would make future upgrades difficult.
Even if you pay a developer to handle these tasks on your website, you'll still want to learn the particular strengths and quirks of your chosen CMS. This will make you more efficient and confident as you post and manage your content. Plus, the more you know about these features, the more new ideas you'll get for your site. Invest some time in learning your CMS, and the payoff will be bigger than you think.