There are two ways this achievement/trophy can be obtained, and both require 750 points to perform:
Recommended method: Use the starting room elevator, open the power room and the power, then get to the roof by using an elevator from the power room. There, the player can see the dragon. This method is arguably the fastest and simplest both in solo and in co-op.
Trample Steam method: Open the door in the starting room, drop down two floors and build the Trample Steam, then use it to fling onto the roof of the opposite skyscraper. There, the player can see the dragon. This method works best with four players as each player can carry a part, but is also viable in Solo as the Quick Revive elevator works without power. The method is also viable in PC with only two players, as by spamming the pickup button each player can walk with two parts and drop them to the lower floor.
Once getting to the roof, the player has to stand in front of the Dragon sculpture near the Polarization Device.