To check paid sessions with a single learner, open the Sessions tab in your LeggUP Lab with this learner. The session is paid if the coaching plan has a "Paid" status!
Also, you can open a calendar to see the paid sessions that are not scheduled yet. These are the sessions that require your attention.
All these sessions can be found in a pool of sessions on the right side of the calendar. Use filters above to specify your search criteria.