Hello. I am new to the file share thing in Halo Waypoint and I am trying to figure out how to watch some of the films some people posted and I don’t know what to do to watch the videos. So if anyone could respond how to watch films from the file browser that would be great. 
You cannot watch user films uploaded to fileshare through the Halo Waypoint website or mobile apps.
What you need to do is sign into waypoint with your xbox live account and click on “send to xbox” under the film you want. The next time you boot up Halo 4 while signed in to xbox live the films will be downloaded to your console and will appear in your local files menu.