How to properly connect plugins to kceditor?

Question

JavaScript

Good day! Dear! Please do not drive to read the dock, but tell me how to connect plugins.
In general, I downloaded and connected kceditor to the page, attached it to the textarea by:

<textarea id="editor" class="text" name="text"></textarea>
<script type="text/javascript">
  CKEDITOR.replace( 'editor' );
</script>

downloaded and placed this plugin in the plugins folder: ckeditor.com/addon/quicktable
in the ckeditor config file in the settings added

CKEDITOR.editorConfig = function( config ) {
    config.extraPlugins = 'quicktable';
};

but nothing happened... I tried to connect another plugin: ckeditor.com/addon/youtube

CKEDITOR.editorConfig = function( config ) {
    config.extraPlugins = 'quicktable';
    config.extraPlugins = 'youtube';
    config.toolbar = [{ name: 'insert', items: ['Image', 'Youtube']}];
};

Again, to no avail, I tried a full refresh ctr+f5 on the page and nothing appeared.
Tell me how to connect plugins correctly?