How can I add a video, for the Video Selection option?

The fastest and most basic way to do so is to use the Sharing URL, which can be collected by following the below steps:

1.) On a computer, go to the YouTube video that you want to embed.

2.) Under the video, click the 'SHARE' Option

3.) From the box that appears, copy the URL using the 'COPY' button already present:

4.) Paste the code into place here in the Video URL field, in your Video Selection's 'Add Video' menu: 

5.) Remember to click 'Add Video Option' in the bottom-right corner, after filling out all your other details, and then click 'Add Section' on the page below.