Here's the spoiler:
Put one Vapor Condenser on each of the three animal houses in Jefferson's camp. The animal houses look like igloos but with an animal sticking out the front. To get to the animal houses, start at the entrance to the Southern Slurries and go a little up and turn all the way to the left. Cross the bridge and keep going left until you see the animal igloos. Hope this helps!
Enjoy the Aetherlight!
P.S. As for fighting the yeti: Try to get a team of 3 people total to fight him. It's much easier that way because you can coordinate attacks. Also, right before the yeti does his Yeti Ice Slam, use the fire cane to attack. The fire cane will light you on fire and drastically reduce the amount of damage done by the Yeti's attack. Also, make sure to bring PLENTY of Aether to heal yourself if necessary!