Place the Facebook box
In the "Facebook" section in the "Embed" tab of the Add panel on the left side of the editor, there are templates for embedding the Like button and the page plugins, which you can place by dragging and dropping the templates in the format you want to use.
Get the embed code
To change the content of the placed embedding template to anything you want, use the following page to get the code of the format you want to embed.
After copying the generated code, return to the design editor. Open the details panel from the <div> at the top left of the code box, paste it into the "Embed box" field, and you're done placing the Facebook content.