Welcome to Android Central! It would really help if you registered on this forum, so that you can continue your discussion in the thread you created:
https://forums.androidcentral.com/as...ml#post3754828. If you post questions as an unregistered guest, there's no way for us to see which questions you posted before. Also, be aware that we get hundreds of new questions every day, and it's easy for a question to get lost in the crowd (which is why it helps to register, so that you can bump your post if no one responding within the first few days).
For your question, it always helps to say which phone you have. You say that you want to play videos from your gallery -- are these videos you took with your camera, or video files you downloaded from the web? Playing a video from the gallery can be accomplished by simply tapping the video thumbnail. If it doesn't automatically play, then tap the Play button that shows up in the center of the video frame.
