Welcome to the sound reader! Basically it shows you how much sound you're making using lines, the higher the lines, the more sound you're making. If you're not comfortable with screaming at your device, simply turn up your volume and hold down the space key so the project can analyse the volume of the music*, but just a warning it works better the other way( the one with you making noises and yelling at your laptop) Up arrow key to clear and start again. You might think this isn't accurate, but it is - it's just that the lines happen to show the volume a second after the sound hits.
* the music is Electro-Light. All art and coding are by me.