Your civilization is already very well established on this planet. Because it is not only strategically important in the war, but here you can get many useful resources.
However, this "tidbit" could not remain without attention. And here you were attacked. Try to take care of a good defense of your base and destroy all the enemies that will try to pass your defense.
In the command menu, select the units for Your hardware. The battlefield, choose allies by clicking on them. Click on the ability, if available, to use them. Control with the mouse.