Customer or Transaction details are shown in the lefthand side of the Alert page view. You can adjust which fields are linked to search (blue) in Schemas.
Link to search page toggle is used to link specific field to search page in UI. Linked field's link will direct one to search page where field will be used as a filter to search by.
All Person or Transaction attributes are shown in Alerts, regardless of whether they are set as 'Hidden' in Schemas.
Data fields that have matched are highlighted in yellow.
If you don’t notice any highlighted data right away, you might want to check nested data fields - sometimes matched data is there!