Videos can be displayed on your slides, linked from the following platforms: Youtube, Vimeo and Wistia.
On the Content editor, Go to Add Element > Video. You'll get the slot to paste your video URL link, from the platforms mentioned above.
A preview Image will be displayed.
Keep in mind while you present, when you get to the video slide it will automatically play in full screen. Therefore, you can't have more elements on the slide where you added a video.