You can embed content from an external source, such as a Google Slides presentation or game, using an iframe.
Add the iframe code to the Source Code field in the Content Editor, replacing URL with the address of the content you want to embed:
If the content does not display, check that the external website has been whitelisted under Actions > Configure > Site Settings > Integration > External Sources. YouTube and Vimeo are whitelisted by default.
The external site must also use HTTPS and allow its content to be displayed within an iframe. Some websites prevent this.
Make sure the iframe code does not contain JavaScript, as this will be removed by the Content Editor for security reasons. Where possible, use the official embed code provided by the external website.