Example, man ls:

NAME
 ls - list directory contents

SYNOPSIS
 ls [OPTION]... [FILE]...

DESCRIPTION
 List information about the FILEs (the current directory by default).  
 Sort entries alphabetically if none of -cftuvSUX nor --sort.

   -a, --all
          do not ignore entries starting with .
   .      .
   .      .

• Not always easy to follow — but worth persevering!