8-bit games were not always intuitive, but they did at least come with a manual!
8bit.mx is a machine that produces 8-bit mixes.
On the left is the song editor. You can add your name and the name of your song. It also lets you edit notes. When you have some notes, try clicking the "play" button to hear them.
On the right are the notes. There are three types: bleeps, bloops, and ksssh. They start out empty, unless you are editing an existing song. To add notes, you click the "add" buttons.
When you add a note or click on a note, an editor for that note will show up on the left. You can change it between a note or a rest, and you can delete it. Notes have a starting volume and a length, which are the "vol" and "len" bars. The /'s and \'s let you make a note finish louder or quieter than it started. bleeps and bloops have a pitch that you can change, and the default is C-5, known as "middle C". Bleeps also let you make the pitch rise or fall, with the ^'s and `'s. kssshs don't have a pitch, but there are several types.
Anybody can edit any mix, but don't worry: your song won't change. Every edit creates a new version of a song. So you can show your music to a friend, they can change the mix, and both versions will still be right there.