1. With an SCP client,  WinSCP for example, download the contents of /var/customizations to your local machine.
2. Make copy of the index.html file and rename the file to an appropriate file name.  index-gridguard.html for example.  

Edit the index-gridguard.html file to add the style elements as shown above. Changes have been highlighted in pink.

Add a form field for gridId and add the gridpanel element to paint the grid in. Changes have been highlighted in pink.

At the end of the file, add references to Javascript files and add the Javascript code as shown above. Changes have been highlighted in pink.

Once the files are altered, upload the changed files back to the NetScaler / AGEE appliance.

After the files are uploaded open a shell command prompt session.  Now execute /nsconfig/nsafter.sh script. This will apply the changes to the login pages.

After all the customizations have been applied, this is what the new login page will look like.