The content component (com_content) is what you use to write articles. It is extremely flexible and has the largest number of built in views. Articles can be created and edited from the front end, making content the easiest component to use to create your site content.
This is a module where you might want to add some more information or an image, a link to your social media presence, or whatever makes sense for your site.
You can edit this module in the module manager. Look for the Side Module.
Congratulations! You have a Joomla site! Joomla makes it easy to build a website just the way you want it and keep it simple to update and maintain.
Joomla is a flexible and powerful platform, whether you are building a small site for yourself or a huge site with hundreds of thousands of visitors. Joomla is open source, which means you can make it work just the way you want it to.