1. Open Jaunt Player. On launch, a blank playlist screen will be shown or the last saved playlist will appear if one has already been created.
2. Double click on a video to start playback or select the item and select the Play button in the lower right corner.
3. A playback window will appear. By default, the playback dialog is in windowed mode but that can be expanded to full-screen playback by selecting Options>Windowed and deselecting.
4. If you have a VR device plugged into the computer, the video will automatically play in the headset in stereo mode.
Tip: Recommended using windowed mode at all times on Windows OS, because Oculus Rift display is shown concurrently. On OS X, windowed mode is appropriate when not using an head mounted display.
For more info on playback controls please view this article.