No worries.
It is about 95% standalone. It has its own install location, appdata location, shortcut. What ever printer or filament or process presets you make in FOS doesn not affect what happens to Snapmaker Orca or original OrcaSlicer. the 5% is it still needs your snapmaker login to communiate to printer over the internet. I have a new version coming out mostly likely today, and I highly recommend grabbing the latest build. It fixed some preset issues. I will add detailed update info once I have it done and tested.