There are some folks on the Discord who have been working on the Halloween Easter egg puzzle, and it was suggested to start a thread here on the forums about it. I'm thinking this one should do nicely.
Let's start at the beginning by analyzing the "Transmission"
0:00 - 0:06: It was a dark and stormy night. What looks to be two MACV soldiers are on sentry duty outside a large tent, somewhere in the jungle.
0:07 - 0:19: Interior view of the tent. Two more MACV soldiers are seen with a third man dressed in civilian clothes. There is a table with a radio set, as well as a mapboard with some photos and markings. At 0:08, a transmission comes across the radio in Morse code.
0:20 - 0:32: The scene cuts to a MACV-SOG team patrolling carefully through the jungle.
0:33 - 0:40: The team has halted after discovering a U.S. helmet on the jungle floor. There is a bright flash of lightning and then thunder.
0:41 - 0:51: Cut to a view of the jungle at night, fade to black.
Clue #1 is the Morse code message. That will lead you to Clue #2. However, there are possibly additional clues to be gleaned from the video, namely the map with its markings and attached photos.