The construction of a small, village-sized colony has been completed. 20 housings now dot the landscape claimed by the UFO fleet. In addition, there seems to be a larger structure in the center of the colony. It is a gargantuan, pure white rectangle with no visible windows and seems to have no entrance. The building phase is done for now.


Now, it is time to make it more habitable. 

A green forcefield covers the claimed area, beginning just at the edge of the claimed surface.

All of the aliens go inside as a sudden heatwave envelops the claimed area. Soon all the grass, plants, trees and anything else green starts to sear and burst into flames. The rectangular structure faintly glows red during this event.
After every bit of grass and other plantlife has been burned, UFOs colored a dark red fly around at a steady pace while shining down a bright orange beam down at the ground from the bottom part of the UFO, the dirt is converted to a reddish brown dust, like that on the surface of Mars, only it is more vibrant and there is a bright red fog covering the ground. Soon the entire claimed area is converted into a Martian landscape, and the heatwave cools down to the temperature of the surface of Mars. The gravity is also changed to exactly how it is on Mars, and the atmosphere slowly begins to morph, like almost everything else, into how it is on Mars.

The forcefield seems to retain the conditions inside the colony and keep them from changing, even the gravity.
Now, it feels a bit more like home.

Most of the UFOs pass through the forcefield and fly off back into space to never be seen again. Only a fraction of the UFOs remain, and they go up to the rectangular structure. A small panel opens up as the UFOs enter it in a single file line. Just as the last one goes through the panel closes up seamlessly.

Now everything is set up.