To add that code to your website:
  1. Navigate to the page that you want to add the content to
  2. Drag the Embed box to the page and wait for the Dotted rectangle to appear before dropping the box
  3. Click the Gear Wheel on the Embed Box 
  4. In the text box that appears paste the Embed code from the 3rd party site 
  5. Click Save

When you view the Webpage you will see the embedded content that you inserted. When you go to add videos to a Pushpage, the ability to directly embed isn't available, but an alternative is to upload this information directly to the App through:
  1. OnMessage
  2. Content
  3. Videos
  4. Navigate to your Pushpage
  5. Edit the section you want the video to appear in
  6. Insert an Image into the page
  7. Select the Image and click the Chain Link 
  8. Insert the URL from the Video you want to add that you uploaded to the Video Content Section
  9. Select whether you want it to open in the same page or a different page in the Target Section
  10. Click Insert
  11. Save the Page
When you Preview the Pushpage, the Image is now clickable and will take the viewer to the Video. For continuity remember to make sure the image name has no spaces or else it won't display in some email clients.