The Proto.io Player is accessible from the 'Preview' button on the top right of the Editor. It opens a new tab in which you preview your project to experience how it looks and feels. You can try out your interactions and animations by using your mouse. You also have the option to navigate between the various screens, using the list or a thumbnail view of the screen browser on the right.
The vertical toolbar provides tools related to the Player: show/hide sidebar, zoom, refresh preview (reload project), change device orientation, show/hide interaction hotspots, show/hide click effect, change device skin color, and enter fullscreen. The show interaction hotspots feature, which can also be activated by pressing the SHIFT key, highlights the interactive areas on the screen.
The Editors’ comments toggle button enables and disables the comments and annotations feature among the users who have edit rights (see Setting up users). Comments and annotations facilitate the communication and collaboration between team members.
Send to mobile is a quick way to send a link to your phone (via SMS) for previewing your prototype. You will be prompted to open it in the Proto.io app.
You can also watch the relevant video tutorial.