I would recommend you to watch first 16 seconds of video properly. It seems you have not selected the correct layout option to appear the drag and drop section.
Here is the link
Do let me know if you have any questions.
Thank you I did. Please see the picture. I am able to see the custom layout. But in difference to the video my screen is NOT displaying space to drag and drop. See how in your video there are two columns one to select what to add and another on your left where you actually drop and move around things.
See the picture, that space doesn’t exist on my end.