To download a class to your Android app, slide the Download toggle to the right (toggle located to the right of the class title). The bar will switch to grey and it will say Downloading. Once you select download, a progress bar will appear at the bottom of your screen.
Your downloads will remain available for 30 days from your last activity logged on the app as long as you were online. You can download individual classes or complete collections.
To use the app in offline mode, your device will need to be disconnected from data and WiFi. You can do this by setting your device to airplane mode.
Remember that logging out of the app will remove your downloaded classes. If you want to keep your downloaded classes, you can quit the app and stay logged in.