You can add a variety of external content to your website using the Embed Code element. First, drag the element to your page wherever you want the embedded content to appear.
Next you'll need to get the code for the item you want to add. The example in this article uses a video that is hosted on Vimeo.com.
Once you have copied the embed code, click inside the Embed Code element and select Edit Custom HTML. Then simply paste the code in place.
When you click outside of the element, your content should show up on the page, though there are some types of code that will not display anything in the editor. In either case, you'll want to publish your site to make it available to visitors.