Here are a few pieces composed in µO: Suspension of Belief, Ressac, Bulle qui rulle, Flying Bugs, Tout va bien (merci), Lithorale, Mesures dragoniennes, Etude pour hang, Blue glue.
Download the ready-to-go 316 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.
.sarfile, and start again from a new copy of the base folder.
.sarpackage are available from this page: http://map.squeak.org/package/90a2baac-b877-4412-8280-0b148f85c415)