Using Gnus and Gmail

[Lorenzo Isella]

Dear All,
I am giving a second try to using our favorite editor to read emails.
After googling here and there, I decided to give gnus a try.
Various attempts did not work very well, but the following blog was 
useful to me:
http://asimakov.blogspot.com/2007/11/imap-gnus-gmailcom.html
Basically, I can now read/send emails within gnus, but I have a number 
of questions:
(1) If I try to subscribe to a group, I see the INBOX group, but not the 
SENT folder I have on google.
How comes?
(2) How can I add a second account? Let alone using gmail feature 
allowing you to send emails on behalf of another account of yours?
(3) Is there anything like a cookbook? I would have a lot of questions 
(how to organize emails, how often gnus should check for new emails, 
filters, how to create new folders and so on and so forth).
It does not seem to me that everything is answered by the manuals in
http://gnus.org/manual.html

Many thanks

Lorenzo