Composer problems

Hi everyone,

I’m searching the web 2-3 hours to learn about Composer, but still nothing. I’m looking for way of installing yii2-jui:

In my XAMPP Control Panel I click on XAMPP-SHELL button and I don’t know what to write there. Is there some tutorial. I’m looking for http://www.yiiframework.com/extension/yii2-ckeditor-widget/ this extension too…

Best regards,

N.

https://getcomposer.org/doc/00-intro.md