Ive seen on YouTube, some more advance players use a Free Camera mode, or they are able to see through the eyes of a player. I looked all through the game commands, and couldnt find any command for this. Is it a mod or is there a special way to do it?

Press 3 or 4 to see through Tori(3) or Uke's(4) point of view.

Press 2 to get free-roam type of camera that you have full control of.