⌘S writes a .sialk file to ~/Documents/Sialk/.
What is in it
Every layer, where it points, its mix, and every parameter value and modulator. Reopening it puts the set back as you left it.
⇧⌘S saves it somewhere else, the show takes that file's name, and ⌘S goes there from then on.
What is not in it
Your sketches. A show references them where they live; it does not copy them.
That is the important sentence on this page. Keep editing your sketches in your own editor, the show opens what is there now, not what was there when you saved. A set can be rewritten between soundcheck and doors without re-saving anything.
Sialk tells you if a sketch has moved or changed since the show was saved.
When a sketch cannot be found
A missing sketch keeps its place in the stack, marked not found, with its
mix and its modulators intact.
Plug the drive back in, reopen, and the layer comes back exactly as it was. And saving in the meantime cannot lose it, a show saved with a missing layer still carries that layer's settings, so the recovery works even if you saved twice while the drive was out.
This is deliberate, and it is the failure that ruins a night: your work is on an external disk, the disk is in the other bag, and the file you saved at the venue has quietly forgotten a third of your set.
Opening one
Double-click a .sialk file, or open it from Sialk. Opening a show replaces
what is loaded, save first if you want to keep it.