Keynote How to include several video clips continuous play

I am trying to include several movie clips from YouTube in either a single slide or to set up several slides to play one after another. I work in a long term hospital and we are having a New Yeras Eve Party and I want to have celebrations/fireworks from around the world playiing behind the musician who will play at our party. I have used keynote for many programs including video clips but always click on slide to start video. I would like to press play and have them all play one after another. Thank for any assistance. I have searched YouTube for tutorial but not really having luck. PowerPoint would work as well, if that's easier. Thanks and Happy New Year!