The information to be shown is normally collected from all agenda
files, the files listed in the variable org-agenda-files.
org-agenda-file-to-front)Add current file to the list of agenda files. The file is added to the front of the list. If it was already in the list, it is moved to the front. With a prefix argument, file is added/moved to the end.
org-remove-file)Remove current file from the list of agenda files.
org-cycle-agenda-files)Cycle through agenda file list, visiting one file after the other.