If you see Submit Moderation Request and click on it, you will be taken to another page.
Here, you can enter a message to your web host to request permission to install this addon script. Then click on Submit Request and an approval or denial message will be sent to your email when the web host has approved or denied your installation request.
If your request is approved, the addon will be installed automatically and you can start using it once you receive the email. If your request is denied, the addon will not be installed. You will need to contact your web host if you believe you have been denied in error.