An old post, but hopefully I can help someone else who stumbles upon this.

The way the map is laid out there are several large groups of Xenites spread across the map. Each group will charge your base at a predefined time, although at least one seems to only charge when you run into it (it's guarding a water spring). Finally, there's an enemy base in the upper right of the map that does nothing; it has no production capabilities but needs to be destroyed to finish the map, along with all enemy units.

At the start, crank down the game speed to minimum. Your goal is to come out of the opening in as good a shape as possible. Rope all your combat units together and put them at the top of the base where the first charge is coming. Set Independence to High so you don't have to worry about microing. Even with all of this you should expect to lose the top part of the base, along with most of your units. Fortunately, the game already gave you a second defensive line right above your Vehicle Bays. This is one of the lines you will need to hold, along with the two sides and bottom of the base.

What I found worked the best was to focus entirely on putting up a wall of defenses. And I do mean wall. Plug every gap you can with a Heavy Rail Platform. So at the start, while you're moving your units up make sure to upgrade your HQ and start cranking out Construction guys. If you get a solid wall of turrets you should be good to go; you might lose one or two here or there but you can rebuild it before the next wave. Make sure to keep your power up as well. I'd recommend using the Freighters from the power plants to collect water from the spring that's slightly above your north defensive line; you might lose a few but the increase in cash flow to be quite helpful.

With this wall up you should be able to weather all the major waves. At that point you should start pumping out Spider Bikes to clear the map. There's a fair amount of hills and the Xenites can climb, so you want the mobility in order to find every one.