Community Builder version 2.0.8 and higher
Installing CometChat as a Community Builder plugin.
Step 1
Log in to Joomla administration panel and navigate to Extension Manager.
Step 2
Click browse and upload communitybuilder.zip file. Click Upload & Install.
Step 3
You will receive Installing component was successful message. Now navigate to CometChat under Components.
Step 4
Click browse and upload cometchat.zip file. Click Install.
Step 5
Once you receive CometChat has been successfully installed! message, click Access CometChat Admin Panel button.
Step 6
Now click Additional Settings. 
Step 7
Select the user groups from whom CometChat bar should be hidden. 
Step 8
Finally, click Save Settings.
Upgrading CometChat
To upgrade CometChat to its latest version on your site, download CometChat package from https://my.cometchat.com/. Unzip the cometchat_UNZIP_FIRST.zip and upload the new cometchat.zip and click Install.
Community Builder version lower than 2.0.8
Introduction
This guide will help you through the installation process and get CometChat running on your site. Installation is very straight forward, only taking about 5 minutes from uploading the files to viewing the CometChat bar on your site. Before you begin, you will need an FTP client, if you do not have one, some popular solutions include FileZilla (free) or CuteFTP (trial). You do not need programming knowledge to install CometChat, but a working knowledge of FTP functions is a plus. This guide assumes that you have successfully downloaded the latest release of CometChat and have the zip file “unzipped” and ready to go. If not, you can download the package from the Members Area. The instructions will term the zip file you downloaded as cometchat.zip.
Uploading
At this point, you should have the zip archive cometchat.zip and find a single folder- cometchat. If you don’t know already, find out the folder in which Community Builder is installed. If you access your Community Builder site via http://www.domain.com, then look for the webroot directory. The webroot directory is usually public_html or www, but this varies from server to server so if you’re unsure, contact your hosting provider. Using your FTP client, copy the cometchat folder inside your Community Builder folder. e.g. http://www.domain.com/cometchat
Installation
Step 1
You should now run the installer file through your web browser by entering the URL to it into your browser address bar (if you have followed our example, type in http://www.domain.com/cometchat/install.php, naturally substituting domain.com for your web address). If the installation was completed successfully, then two lines of HTML code will be displayed on your screen. Please copy these two lines. Also, the page may display a list of files and folders which may require additional permissions. Please CHMOD those files/folders to 777.
Step 2
Now edit your template header. Login to your Joomla Administration (usually http://www.domain.com/administrator) Under the Extensions tab, select the Template Manager option. Now select the template which has a star next to it i.e. the template in which you want to add CometChat. Click on the Edit HTML button (top-right corner) Immediately after the opening head tag add the copied code:
<head>
<link type="text/css" href="/cometchat/cometchatcss.php" rel="stylesheet" charset="utf-8">
<script type="text/javascript" src="/cometchat/cometchatjs.php" charset="utf-8"></script>
</head>
If you are unable to find <head> tag, then please add the code manually using this guide.
Now delete install.php file from the cometchat folder. That’s all! Now log-in to your site and you will be able to see the CometChat bar. For customizing the text, icons, plugins, themes and modules, please refer to the documentation for Administration Panel.