Joomla 3+ comes with two sides, the front end and the back end. The front end is what the visitor sees when he/she types the domain name for your site into the address bar of a browser. The back end, or Administrative interface, is where you go to control the website. You use the Admin side to set up menus, install extensions, change settings, add modules, etc.

To get to the Administrative Interface of a Joomla 3+ installation, you must first login. Open up a browser, Chrome, Firefox, Internet Explorer, Safari, or Opera, and enter your domain name followed by a forward slash followed by the word administrator.

http://websitename.com/administrator

adminloginscreen

You will come to a login form.

This login form is where you type in your login and password that was entered during the initial configuration of the Joomla site.

To log into the back end of a Joomla site, your user account must be at the Administrator or Super Administrator access level. 

The Administrative Interface

The first screen you come to is the Control Panel. Along the top are drop down menus that take you to the various sections of the Administrative interface.

System Settings

First there are the System settings that you start off with when you install your site.  These are things like your site name, hosting information, database information, site email address, etc.  

Content: Categories and Articles

Then there is the Content.  Content consists of Categories, Articles and Media.  Categories are the different focus areas that you have on your site. They are used to organize and display your Articles in a meaningful way. Articles are where you put the words, the photos, the videos for the content. Media is the images and the videos.

Menus

Then you have the Menu or Menus.  This is the navigational aspect of the site.  They can be displayed across the top, down the side, at the bottom.  There can also be lists of articles or categories contained in the content area itself.

Components

The Components are the functionality of the site or what Joomla calls "mini-applications".  Joomla comes with a standard set of components, but you can install what are called Extensions that add specific functionality.  The standard set of components are Banners, Contacts, Messaging, Newsfeeds, Search and Weblinks.  Components can either be something to modify the Administrative side of the site and/or the Front End of the site.

Extensions

As far as Extensions go, they list the most popular and safe ones at extensions.joomla.org.  They can be free or they require purchasing.  They are created by third party companies that are not part of the Joomla.org. Some examples of extensions are ones that create slideshows, membership tracking, social media plugins, shopping carts, etc. Joomla 3.+ now allows you to see a display of Extensions and upload them directly to your Joomla installation right through the Administrative Interface. You can also download them from the 3rd party provider and upload them through the Extension Manager as was done with earlier versions of Joomla.

Modules

Modules are the things that you put on the side of your content (though they also can be included inside the content).  They are created using Module Manager. Modules hold things like your sites menus, advertisements, specialty links, archived articles, breadcrumbs, Newsreels, Search boxes, etc. Modules are placed into what are known as Positions.

Modules are assigned to Positions. Positions are established by whatever front-end template you are using.  Some templates have numbered positions, others have named positions. Positions are areas of the page like the left column, the top, above the content, below the content and the footer area.

Plugins

Plugins are specialized event handlers.  They often are packaged in with the extension that you uploaded.  In some cases you need to go to the Plugin Manager and activate them for a specific task to be preformed.

Users

Users are all of the people that use your site.  Users, other than the general public, are assigned User Names and given Passwords, the are assigned to a User Group.  The User Group a assigned Access Level.  The Access Level defines what parts of the web site the Users can access, as well as what they can edit, delete, create and control.

Templates

Templates determine the basic layout of the site. Usually they modify the Front End but there are Back end templates as well.  Templates set where the Positions are located: ie the columns, the logo, the content area and the footer.  Some third-party templates have extensive options that you can select to minimize how much styling you need to do by hand.  Templates contain the CSS stylesheets where you can go in and alter the colors, fonts, and physical features of your site.  They can be very specific on the look and layout or they can be minimalistic, letting you manipulate how you want the layout to look. The default Template for a Joomla 3.+ installation is the Protostar Template.

Languages

The Language that Joomla uses is also something that you can control. Joomla is used all over the world, and the Administrative Interface can have one or many languages assigned to it.  You may need to install an Extension that allows multi-lingual support. Joomla 3.+ has greatly expanded the language functionality.