adding ckeditor color button and font size
You have to create the folder yourself as the docs say.

You can do this with command line with mkdir libraries in the webroot (where the /core folder is), or with a window and New Directory (New Folder) in either Windows / OSX.

Your application structure will then look like...

/core
/libraries
/modules
/themes


and so on.

All thats left is to download the JS plugin from ckeditor.com (v 4.5.x), unzip it, and place it in the libraries directory.