Adding Javascript file to modern page

How do I add Javascript file to modern page within Data View Plus web part

1. Add Data View Plus web part to the page

   

2. In template editor go to Scripts tab

3. In script editor create new script loadJS:



4. In the script editor add the code:

 

   var script = document.createElement('script');
   script.onload = function () {
    //do stuff with the script
   };
  script.src = 'https://kwizcom.sharepoint.com/sites/st/SiteAssets/Test1.js';
  document.head.appendChild(script);

5. Go back to HTML tab and add the code there: