Please check out this video to see all the Watch app functionalities, how to change the Aspect Ratio, how to change the video to HD Action Mode, how to switch from photo to video mode and how to flip the cameras.
You may also view the "How to Use the Wristcam App" on your Watch by opening your Wristcam app on your Apple iPhone, then select the icon on the lower left to see our newsfeed. There you may view the How To Watch App, noted also as Quick Tips (scroll down to see the video).