Here are a few pieces entirely composed in µO:
Tout va bien (merci), Ressac, Rauquosphère, Bulle qui rulle, Lithorale, Blue glue, I'll get there, again, Day one, Busy Claude is late again, Lava me, baby, Nouménal blues.
Download the ready-to-go 347 image archive, unzip it anywhere and start
That's it; you don't need the following instructions.
squeak.exe: you will see the Squeak window.
muO.***.sarfile, and start again from a new copy of the base folder.
muO.***.sarpackage are available on SqueakMap.