Anytime the mouse is over either the SOURCE or DESTINATION lists, a message appears that shows how to CREATE or CHANGE a backup routine.
as shown in the image above in the CYAN color box
The SOURCE and DESTINATION lists are synchronized
Anytime the mouse is over the green book icon as shown in the image on the left, a message appears that shows how to modify the DESTINATION folder by adding a sub-folder.
as shown in the image on the left in the RED color box