How to play a song where all players in the game hears the same song which is synchronized?

I'm making a music player and I want everyone to hear the same music at the same time.

Just add the sound to workspace then everyone should hear it at the same time.

To make a sound play for the whole 'World', you would place the sound in the Workspace. This will allow it to be heard from anywhere. If you only want it to play in one spot, then place it inside a brick. To start the audio you would use :Play()

audio  = game.workspace.Sound

wait(5)
audio:Play()

I hope this helps. If you have any further questions, just leave a reply to this comment.