Adding a new account to your library is easy! If you are using an Android or iOS device, tap 'Add Source' on the bottom tab bar and select one of the available sources. For Windows and Mac desktops, a new account can be added by selecting 'Add Source' in the top bar or in the Settings menu. 

Once you've selected a source, you'll be prompted to sign into your account using your device's default browser. The browser window will then close, allowing the syncing process will start. You'll then see content start to appear in your library.