If you'd like to add a video to one of the pages of your website, you can use the text editor that is available on many of the setup pages.
Once you've uploaded your video, obtain the link to that video. To do this for YouTube, simply click on the 'Share' button.
Then, click on the 'copy' button.
Within a text editor widget on your site builder, click the 'video' button.
Then, paste the video link into the field provided and click 'Insert Video'.
Your video will be automatically centered on the page that you place it on.