Enter your email & choose a password at https://rumbletalk.com/. Then click on the "Get Chat Code" and get the code for Joomla.
Upload the rumbletalkchat module to the "sites/all/modules/" directory.
Go to Drupal "Administration", then to "Modules".
Look for RumbleTalk Chat module and select it, then click on "Save configuration"
Go to "Administration" -> "Configuration" -> "RumbleTalk Chat", and insert RumbleTalk Chat code. Optionally set width and or height (both percents are pixels are allowed). Example width or height values: "100px" or "100%" (without quotes).
Click on "Save configuration", after that you should see success message.
Go to "Administration" -> "People" -> "Permissions", look for "rumbletalkchat module", select "Access RumbleTalk Chat" permission for all groups that should be able to see the chat.
Click on "Save configuration", after that you should see success message.
Go to "Site configuration" -> "Input formats" -> "Full HTML", select "RumbleTalk Chat" filter. and click on "Save configuration". After that you should see success message.
Go to "Create content" -> "Page" (or "Story" etc.). Create new node, and insert [rumbletalkchat] shortcode anywhere inside node.
The shortcode will be replaced by RumbleTalk Chat window.
This module uses cache, if you using cache (as you should), you may need to go to:
"Administration" -> "Site configuration" -> "Performance"
and click "Clear cache" to propagate changes for anonymous users.
If you see "You are not authorized to view RumbleTalk Chat, please configure access permissions." error message.
Make sure you followed "Setting up Permission" properly.
If you see [rumbletalkchat] shortcode inside article. Make sure the module is enabled, and you followed properly first step from "inserting RumbleTalk Chat to Nodes".
Go to Drupal "Administration", then to "Site building" -> "Modules".
Search the "RumbleTalk Chat" module. Un-check the check-box placed on left side of the title.
Click on "Save configuration". After that you should see success message.
Full instructions can be found here: https://rumbletalk.com/