This answer was previously posted on Stack Exchange, before I noticed the question was being moved.
Each numbered point in your quote applies in turn to each of the three characters.
If the first character is 'r', the file is readable
If the second character is 'w', the file is writable
If the third character is 'x/s/S', the file has the executable and/or set-userid/setgroupid property as appropriate
If the character is '-', then the file does not have that property.
The first three characters (after the directory identifier) apply to user permissions, the second three to group permissions, and the third to everyone else.