Products typically individual shades, but not always. Looks are groups of shades in the Portal. Learn more about use cases and content types.
Often a team member managing data and/or application integration that requires lots of specific data may actually create the products first and then handoff for makeup calibrations.
Use & create presets, especially when doing lots of similar products (see Best Practice)
First passes/testing calibrations can be done on any device and anywhere. But when finalising calibrations always do so in your end users' target device (hardware) & environment (lighting) to ensure what you want users to see is what they are likely to see. Otherwise the shade colour and intensity (opaqueness) could look drastically different. Read more about why hardware & lighting are important to calibrating colour.
If you are targeting in-store iPads, then calibrate on that model of iPad with similar lighting temperature and strength to the target store.
If you are targeting an in-store HD Mirror, use the exact camera and screen you will deploy with similar lighting temperature and strength to the target store.
If you are targeting web desktop and mobile, use multiple devices amongst Windows, Mac, iOS, and Android and test in a range of real-world, but good lighting (avoid extremes in light temperature and darkness). You will get a feel for the differences and understand how much variance you want to test for.