Xert models your fitness signature based upon how well you perform maximal efforts under fatigue.
See this article for BT types – Breaking Through the Xert Way! – Xert (baronbiosys.com)
Setting an imaginary TED to initiate a phased progression is a good way to learn Xert.
During Base phase only endurance level workouts will be recommended.
Setting Athlete Type to Century Rider (endurance quadrant) means goal focus duration will also be endurance. If you want more variety during Build/Peak phases you can switch to a lower focus duration point (ex. GC Specialist).
How much historical power data did you import into Xert to establish a starting signature?
Another method is to enter known values into the Power Curve Calculator.
Lots of newbie tips posted here – Beginner questions