This can be done solo or with a group. You must build the boat (three pieces) and the projector (two pieces). Each piece spawns in a specific location. The three boat pieces can be found upstairs from the spawn (need to turn on the power), inside the mess hall against a pillar, and in the recreation area next to a stand. With the boat built, head to the boathouse. Grab the reel of film that is on the ground next to the boathouse and then ride the boat. On the island, head up to the cabin and grab the second film reel in the picnic area. Use these to fix the projector, head into the portal and pack-a-punch a weapon.
Here is a video guide with English commentary!
Here is a playlist of guides for this game!
https://www.youtube.com/playlist?list=PL-HeW6XkKdUIS4EclEfJ3...