Vantage Points are marked as little balloons on your map. You'll probably encounter the first one after you completed Chumbucket's tutorial and while you are on your way to Jeet's stronghold. They become visible on your map as soon as you enter a new region.
To conquer a vantage point, making it a fast-travel point and using it's other benefits, you'll have to make sure that the balloon is operational. This is achieved by completing one or more of the following steps:
- Make sure that all tethers, that anchor the balloon to the ground, are cut
- Make sure that the generator, connected to the balloon, is fueled up
- Make sure to lower the balloon to the ground with the controls
- Make sure the balloon is fueled up (you also may have to refuel it later)
To fill up a balloon with fuel you use a Jerry Can on the tank at the side of the balloon, not the control station connected by wires.