Red Hat Linux 6.2 help

[kmi]

Dear all,

It's my pleasure to contact you through E-mail.

I'm sure you're the best one who will answer the following questions.
1.how to list the files/directories within every visible screen but not in
a
  whole?
2.What does the term of block mean?
3.What does chmod g+s, g+t mean? Is it useful?

Thank you.

Best regards,
Kellie