I am trying to develop a presentation program but am having an issue that only the player giving the presentation can see the video/powerpoint that he is showing. Is there a way to fix this?
You’ll need to use Server RPCs to send state to the server for whatever the client is presenting. Then the server will need to replicate that state to all clients via Properties or Multicast RPCs
More info on Replication in general here: Actor Replication | Unreal Engine Documentation