The Navigation Manager - Playing

To play a particular role within a given Unit of Learning, you need to select one of the users in the Course Manager tree (denoted by ). Once highlighted, the play button should become enabled (denoted by ). Click the play button to launch this role in the browser. (If you double click the role node itself it will also launch the role)

You should now see a web browser window open in the opposite pane - similar the following screenshot..