Use the teleporter to reach the PaP room.
Similar to the other Zombies maps, Kino der Toten has a Pack-a-Punch machine that you need to activate in Black Ops 3. That will allow you to upgrade your weapons, at a cost of course. This is how you increase your damage because the zombie hordes are going to get tougher in the higher rounds. How to Pack-A-Punch your weapon in Kino Der Toten
After turning on the power in Kino Der Toten, the backstage curtain rises, allowing you to access additional parts of the map, including the Teleporter.
