Step 1 - Download the DrupalChat module from http://ftp.drupal.org/files/projects/drupalchat-7.x-2.8.tar.gz (direct download link) and save it to your modules(sites/all/modules) folder.
Step 2 - Enable only DrupalChat module at admin/modules as shown below.
Step 3 - Set the access drupalchat permission for authenticated users at admin/people/permissions.
Step 4 - Generate API Key in order to use our servers securely with your website. Go to https://v2.iflychat.com/user/register
Step 5 - Go to Dashboard and Generate a new API Key for your domain name.
Step 6 - Copy the newly generated APP ID and API key.
Step 7 - Go to admin/config/drupalchat/configuration (on your website) in order to configure DrupalChat module. Select iFlyChat Servers as the polling method and paste API Key and APP ID.
Click on Save. That's it!
Optional : To Embed Chatroom in a drupal node, click here.