How to make GUI appear and a sound play when object falls.

Hello, I'm fairly new to the beautiful world of Unity, but that doesn't stop me from trying to make my first game. However, I have reached a point where I need Your help. I have to make it so when the player (in this case a ball) falls of the track, and into void, a sound plays and a gui appears and says something like : You failed. I already have created a script that respawns and returns the player to the start of the level by using y -10 coordinate, and I would like to know if there is a way I can make sound come off and gui appear on a coordinate like y -5, so it plays fully. Thanks a lot for your time and effort.