I am new to drupal. I am using drupal 8.2.5, bartik theme and i would like to add font size&family and colour buttons to the ckeditor. i installed the "CKEditor Font Size and Family" module, enabled it and then at "admin-configuration-content authoring-text formats and editors" i configured "Basic HTML" and "Full HTML" and drag the new available buttons of fonts and size to the toolbar. I saved it and then when i tried to add new content (article or basic page), the editor was completely gone, there was only the field of "summary" available to write something! When i disabled the module, the text editor was back to normal.

Later, I noticed at the module page that the installation process was the following: "1.Download the plugin from http://ckeditor.com/addon/font. 2.Place the plugin in the root libraries folder (/libraries). 3.Enable CKEditor Font in the Drupal admin. 4.Configure your WYSIWYG toolbar to include the buttons."

So I realised i hadn't followed step 2. I don't know where the libraries folder is, although i searched and have no experience how to create it correctly and how to place this plugin there. I read various posts on the internet but couldn't find a solution and then i ended up here. Thank you.