[Help Needed!] How to switch the video and avoid audio overlapping

Hi! I’m totally a new beginner, and I’m trying to do when people touch the button, it will trigger the video and audio to play. I have 3 videos and 1 idle video, I managed to let people switch all three videos by touching different button, but here’s the problem: when user is touching button A and it triggers the video A to come out, but at the same time user accidentally touch button B. At this point, video B won’t show up on screen (because video A is playing at the time) but the audio of video B will be played and it overlay with video A’s audio. The video B will only show up on screen when video A is finished playing.

Question: How can I directly switch video A (with audio) to video B (with audio) without the audio interfering each other, and fully stop video A and its audio when I’m playing video B.