Id like to have an answer too, i've been running around like a headless chicken for an hour. Maybe in the city?

Apparently you have to do the Horde Beacon sacrifice first.

so
there are 2 ways. 1 you grab a helicopter and fly up to the BIG island in the sky (dont do it, it wont spawn any NPCs) or 2 do a horde beacon adn hope it doesnt glitch out and it acknowledges that you did it. then it will spawn the NPCs will all the quests.

There are areas marked on your chart map with a blue cross. They say "teleporter location" Try investigating those a bit. They will tell you to spend a horde beacon at one of two locations.

One of them is in a floating house in "Town" and the other is underneath the Gas Station. You are not activating the horde beacon, you are spending it to open the teleporters.