Let's back up a little to see what your needs are. The mobile apps are generally used more to access your files, rather than backing up from them. That being said, there are a few tricks you can do to back up pictures and videos from your tablets, but that is about it. It looks like they are android tablets, have you already installed the Mozy app on them?
Mozy cannot directly backup your Android devices. The Mozy Mobile app is designed to help you view your files you have backed up online.
However, Mozy does have a feature called Sync. You can utilize Sync to upload files from your phone to your Sync folder. These will then appear in your Mobile Uploads* folder inside of Sync. They will not appear as a different device, but all items will reside in the same folder (or make a folder for each an upload to the specific folder, *you do not have to upload to the specific Mobile Uploads).