Type can be changed at any time but regardless of selection the recommendations will have an endurance focus during Base phase.
The spider chart under Ranking shows your relative strengths and weaknesses compared to the population of Xert users. Types roughly fall into quadrants along the power curve starting with Power Sprinter (20 sec power) to Triathlete (3 hour power).
A round plot indicates few weaknesses whereas a star-shaped plot shows what you are better at. You can elect to work on a strength or weakness depending on your goals and time of year. If you decide to do that you’ll want pick a type in different quadrant.
You can also do this on-the-fly using the Filter option for Recommended Workouts and selecting a specific Focus. In all cases recommendations will contribute to your training so don’t hesitate to experiment. IME the key to learning Xert is taking an interactive approach (what-does-this-do) and not set-it-and-forget-it. 
If you set TED (target event date) in the past XATA will recommend a variety of workouts at the current athlete type (focus duration) whereas a phased progression follows a graduated pattern of focus (see reference link below).
Lots of newbie tips are posted in this thread if you haven’t seen it –
Beginner questions - Support - Xert Community Forum (xertonline.com)
Welcome aboard.
References:
Program Phases – Xert (baronbiosys.com)
Choosing your Athlete Type – Xert (baronbiosys.com)