The inbox is a "waiting area" for lessons.
On the Inbox list you will see student video that has been "assigned" to you via your branded academy. By selecting and downloading one of these videos, the student is informed that you have "accepted" the video for analysis. From this list, use the Refresh icon to check your academy for new lesson requests.
On the Outbox list you will find lessons that you have done that are waiting to be sent to your students on your academy. From this list, use the Refresh icon to begin sending once you have an Internet connection available.
Finally the Sent list will contain lessons that have been successfully uploaded to your academy.