The very first time(s) you launch MuLab App, it will auto-load Start.MuProject and automatically start playing this project.
This project makes it very easy to immediately start having fun with MuLab even without knowing anything about it.
Click in the editor to draw notes and click the various tracks to switch the sound and editor.
As soon as you open or save a project yourself, the Start.MuProject won't be automatically opened anymore on startup, instead a start dialog is shown from which you can choose which project to open:
Tip: You can also drag-drop a MuProject file on this dialog to start with that project.