Javascript not running in WordPress

Hi,

i’m trying to run Js code into wordpress, using a plugin; but can’t make it work.

Here on this Codepen page, you can see the element i’m trying to integrate on my site (ie. a drag and drop feature)

https://codepen.io/galaxija737/pen/pHvEi
And here, this is working properly.

But then, I can’t figure out how to integrate the js code properly into wordpress; whatever plugin i’m using. And idem into JSFiddle, impossible to run properly the script, as you can see…
https://jsfiddle.net/szan6shz/)

For instance using “TC-custom-javascript” plugin; when I add the JS code, nothing is running (i.e the drag-drop feature is not working; like ont the Fiddle) :

I’m really new at Javascript as you can see. If anyone can give me a hand on this. (I guess i miss something is the way JS needs to be written/integrated)

Thanks a lot !

Greg