There are two different ways in which you could include a video in your ePoster/Stack:
1. As a File (MP4)
The first would be to add a File tile from the Tile Library and then add the video file in the Add File box that appears to the right. If you watch video 3 (http://support.ltb.io/faq/) between time 10:20 and 11:05 then you will see how we use the File tile to add a PDF file to an ePoster. To add a video file you would follow the same steps, but upload your video file instead. Make sure your uploaded file is in MP4 format so that it can be played by the internal LTB video player.
2. As Online Content (Using YouTube or Vimeo)
The second approach you could use is to first upload your video to a social media platform like YoutTube or Vimeo. This will make sure that your video is viewable online (and within the Learning Toolbox app). Within Learning Toolbox you can then add an Online Content tile to your ePoster and add in the url link to your online video. Doing it this way will mean that people can view your video within Learning Toolbox itself, they will not need to have any other special software installed. If you watch video 3 (http://support.ltb.io/faq/) between time 9:08 and 10:20 then you will see how we use the Online Content tile to add a Youtube video. for use with Vimeo you would follow the same steps.