Indeed, man = manual although this does not of course mean they are exclusively for the use of guys..... girls are welcome to use them too!
For each command or application there should be a manual page. You access them from the command line in a terminal/console. First type man then the program you wish to know about. For example
man also has it's own manual of course. Try
They can make terse reading at first but they are a great reference when you basically know how to use the command but can't quite remember the syntax or the switches you need. On my system man pages are located at /usr/man
Hope that helps, BashTin