There are tons of CMS out there and they offer various features. Also, the different CMS vary depending on the difficulty of installation and administration - there are easy ones and there are really hard ones. If you are a beginner, Joomla and WordPress are among the top choices for you because they are easy to install and administer and their support communities are really friendly. Of course, this doesn't mean you can't choose another CMS - it is up to you to decide.
In any case, no matter which one CMS you choose, the steps to follow are similar. Basically, these steps include downloading the CMS from its official site, creating the database, installing the CMS manually, uploading your content, adding some extensions, and promoting your site.
Download The Latest Stable Version of the CMS from Its OFFICIAL Site
The first step in creating a simple CMS is to download its latest stable version from the official site. The first thing you need to pay attention to is that you get the latest stable release, not any release you find there. The reason is that unstable releases tend to crash frequently and you will hardly feel comfortable as a beta tester. Additionally, unstable releases are not meant to be deployed in production environments.
The second thing you need to pay attention to is that you are downloading from the official site. This is a rule you should follow when downloading any software because if you get the installation files from a peer-to-peer network or from any other site, you risk getting a fake version and/or malware. Since generally the best CMS (i.e. Joomla and WordPress) are free, there is no reason at all to resort to peer-to-peer or other sites.
Create the Database
After you have downloaded the latest stable release of the CMS you want from its official site, there is one more step you need to take before you proceed to the installation itself. This step is to create the database where your data will be stored. In addition to creating the database, you need to create a database user and assign it a password because these are required during installation.
Technically, you could use an existing database and database user with your CMS instead of creating new ones. However, if you prefer clean solutions, you'd better create a dedicated database and database user exclusively for this installation. Otherwise, if things get messed up in the database, this will affect all the sites that use it.
Install the CMS Manually
Finally, you reached the step to install the CMS. Here the best you can do is follow the installation instructions for your particular CMS. Basically, most CMS install in a couple of easy steps but in order to get things done properly, you need to read the documentation for your CMS and follow the exact steps. Many CMS have a Quick Installation Guide (or something similar), where only the most important stuff is included, so you may start with them.
No matter which CMS you plan to install, a rule of thumb is not to use Fantastico or similar automated installers. It is true that Fantastico and the other automated installers make your job much easier but they have quite a lot of downsides, including potential security risks, so you'd better forget about them.
Now, when your CMS is up and running, you are half done. You need to add content. Depending on how much content you have, this task could be a very time-consuming one. What is more, you need to constantly add new content to your CMS, so don't think that you will do it once and it is done forever.
Almost any CMS comes in the form of a basic module, which offers the features you need in order to have a decent blog/site and tons of extensions, which are not included in the basic install. This principle of modularity is great because you can browse the official site of the CMS developer and the sites of third parties and see what additional modules, components, extensions, addons, plugins, etc. are available.
It is hard to recommend what extensions to get. Different web masters have different needs and they choose different extensions. For instance, if your CMS doesn't offer SEO friendly URLs out of the box, you should get a SEO extension. Also, extensions that list most popular posts or extensions for displaying ads from Adsense and the other networks, are also useful. Anyway, the best advice regarding extensions is to visit the site of the CMS, check what is available, read what users say and get the extensions that seem most useful. You can always add more extensions later, so don't worry, if you can't decide right away which extensions to pick.
Start Promoting Your Site
At this point you have a working CMS. However, you job is still not finished yet. Yes, you have deployed your CMS but if your site doesn't get traffic, your mission is not accomplished. You need to promote your site and optimize it for search engines. Otherwise, your blog/site will not get visitors. Site promotion is a vast topic and we can't cover it here.
As you see, creating a simple CMS is not something a modestly technical guy or girl can't accomplish. It could be time consuming, though. Anyway, the most difficult part is to do it once. Once you manage to create a simple CMS, every time you have to do it after that, it will get easier and easier to do!