From the Camera app in Video mode
In the viewfinder, tap the video thumbnail at the bottom of the screen.
The last video you recorded appears on the screen.
Scroll the screen horizontally to select other videos to watch. You can also tap the screen to display your Gallery videos (and photos) in film-like images at the bottom of the screen for quick scrolling and selection.
Tap the Play icon in the middle of the still image
of the video you want to play.
Tap Photos or Videos, then tap Always or Just once to begin the video playback.
From your Gallery
From the Home screen, tap the Apps icon > the Apps tab (if necessary) > Gallery
, then tap the album you want.
Tap the video you want to watch.
Tap Photos or Videos, then tap Always or Just once to begin the video playback.