Read "perldoc perldoc". :-)

For a beginner all you need to know is

"perldoc -f somefunction" will give the documentation for a perl function (if it exists )

"perldoc -q somekeyword" will search the excellent Perl faqs for that keyword, and will return all the references to the keyword in the faqs. Like "perldoc -q number"

When you are in a perldoc session, and you want to search for a word in it, hit /, followed by the search word and enter. Then that word will be found and highlighted.

To read a module's documentation, it's "perldoc fullmodulename", like "perldoc Tk::Canvas" or "perldoc "MIME::Lite".

For the inner workings of pod, look at juerd's pod tutorial