Slidebean works online, so videos can be linked from online platforms like Youtube, Vimeo, and Wistia. When editing the presentation, go to "Insert" in the upper settings menu bar and select Media, to find the Video element.
You'll get a field to just paste the video URL from the platforms mentioned above.
The video will fill the slide automatically but you can also manually resize and reposition it if you have other elements in the slide.
Keep in mind you'll need to hit the Play button in the video for it to start playing, when presenting.