This is simply an entered numerical field for how many XP (Deluxe) or Advances (SWADE) your character has attained.
As soon as you change this field you'll note that the "Current Advances" to the right or bottom, depending on your screen size, will change and allow you to choose your advances.
Some folks like to plan their characters in advance. We've allowed for this. If you change this XP or Advancement count, it'll not only increase the number of advances on the right or bottom, but it'll also note where you character stands currently.
Depending on your Primary Book Selection, you'll have a list of options here of what type of advancement to choose for each advamcenent slot.
Once you've selected an advancement, more options will appear below the drop-down to help narrow your character's advancement.