at this point:
"A taste of advanced features"
it's written to add this text, on my init.el file (I'm working on win).
(setq org-agenda-files (list "~/org/work.org"
"~/org/school.org"
"~/org/home.org"))
I've done it.
Continuing the tutorial, I find some operation to do in my org file "Press
C-c a t to enter the global todo list"
I do that, but I receive in the *Org Agenda* buffer, the following text:
_________________________________
Global list of TODO items of type: ALL
Available with `N r': (0)[ALL]
__________________________________
and nothing else.