why no audio on video on galaxy 8

[AC Question]

i saw another post that instructed to tap on the arrow once the video started playing. when i did that it brought me into Gesture Control which described swiping the screen to bring up a volume control icon. i tried that but no icon displayed. Why are they making this so difficult and how do i get volume to play? It was the first time i used video and assumed it would just capture audio too but maybe i'm getting no where because i failed to set something to capture the audio? If that's the case, this is crappy design. Please tell me how i play back any audio captured, what the gesture control is all about and if i need to set a setting to capture audioin the future and how i would do that.