How far along are you in watching the Academy series videos? The core principals are covered there with examples.
Ramp rate is used to manage your hours/week commitment and accommodate a changing schedule or to taper or level out (Maintenance = 0).
Most users won’t ride more than 2 hours indoors although any workout can be extended using Workout Designer to generate your own version (Personal folder).
OTOH an outdoor free ride to Focus can be as long as you want it to be.
What type of workouts do you like to do?
You can import favorite workouts sourced elsewhere with an option to convert portions to SMART intervals that scale to your fitness signature.
You can join the Shared Workout Coach Community to expand workout selections.
HIIT recommendations will be as often as your calculated form indicates and what Focus duration point you select or filter by. You can up the ante (temporarily) by adjusting the Freshness Feedback slider.
With Continuous or Challenge ATP and 4-5 stars training load, you are in charge of how often you want to incorporate HIIT into your schedule. Otherwise, a phased progression (TED) will follow a prescribed course of periodization dependent on selected Athlete Type (Focus duration point).
Here are two articles that describe the overall process and how one might use Xert depending on what your goals are.
Xert Adaptive Training Advisor – Xert (baronbiosys.com)
Training Right For Your Event – Xert (baronbiosys.com)
Lots of newbie tips posted here – Beginner questions
Academy series videos – Discover + Improve + Perform
FAQs here – Support Home – Xert