While using Apps on Demand, you'll see the Amazon AppStream Navigation Bar between your browser header and your applications.

Launch app - You can have multiple applications running at the same time. Select an application from the list displayed here. Your current application(s) will remain open.

Switch windows - If you have more than one application running, click this icon to display each of their windows. Click a window to bring that application to the front.

My Files - Access your OneDrive and Temporary Files. Be sure to store your work on your OneDrive. (Work stored in Temporary Files will disappear when you end your session.)

Clipboard - Only when not using Chrome. With other browsers, this is how you copy from an application in AppStream to your local clipboard for pasting into a local application, or from local to remote. Chrome does this automatically. 

Settings - Enable microphone / Streaming mode / Screen resolution / Regional settings. Most people never alter these settings.

Enter fullscreen mode - ESC to exit.