First, create a Elementor Video Gallery widget on Common Ninja.
On the widgets catalog, find the Video Gallery and enter the Editor.
When you're done creating the Video Gallery widget, click on the Save Changes button at the right top corner of the editor.
If you don't have an account on Common Ninja, you'll have to register first.
When you're ready to add the Video Gallery widget to your Elementor website, click the Add To Website button at the top bar of the Editor.
On the window that opens, click the Copy Icon to copy the widget embed code. In the next steps, you will paste this code into your Elementor website.
Now, let's head to the Elementor's editor.
On the Left panel, enter Widgets and scroll to the HTML widget.
You can also filter the widget list by searching for the HTML widget.
Drag and place the HTML widget wherever you wish the Video Gallery to show.
Now, in the HTML Code window on the left panel, simply paste the Video Gallery embed code you've copied before.