The data can be seeded different ways with variable results but the point is to establish a “starting” fitness signature.
Xert will constantly recalculate your signature after every activity or lack thereof (decay).
No need to use recalibrate progression unless there is an issue with new activity data that is corrected instead of flagged (ignored for signature calculation).
Now that you have a starting signature your future rides/workouts will validate that signature as long as that activity includes periodic breakthrough events.
Lots of newbie tips are posted in this thread –
Beginner questions - Support - Xert Community Forum (xertonline.com)