Sounds like you have a problem with your man pages. You should have received a man page after typing man ls. The man or info page for the chmod command gives basic information about file and directory permissions. Your assumption on the three areas for permissions is basicly correct. It is more correct to say user, group, others. That falls more in line with the symbolic notation you can use in the chmod command.
I would look into your distribution to make sure the man pages installed correctly. Another site you might find helpful is The Linux Documentation Project at http://www.tldp.org/.