Click on "Webapps" and on the page that comes up choose the "New Web App" button at the bottom.
Fill in the name (guacamole) and leave everything else as it is.
* Note: If you do not see the "Webapps" option under "Apps" then you need to activate "Advanced Settings" under the "Settings" tab of your Amahi dashboard.
=== Downloading the Binary Packages ===