This article explains the exact relationship between Libraries and Content for Standard Libraries and Cloned Libraries.
What is a
...
Project Library?
A Project Library is a dedicated space for all Collections and consequently Content that are part of these collections. Each active Library and all it's Content is uploaded onto the Rumie App through the Sync process. Note: this includes the Rumie Tablet or any Android device with the Rumie App installed.
...
Once your Library or Libraries have synced successfully on your device, you can start viewing the content. The Content for each Library is unique and you will have a separate view for each of your Library. You can select your Library by selecting the (☰)hamburger menu on your left, navigate to "My Libraries" and select a Library from the "Select a Library" pop-up. Clicking on the radio button (O)next to a Library name and then confirm by clicking "OK", your Content should be available then.
What version of the Rumie App do I require for being able to use Libraries?
...