When you hear the alert tone the government uses to advise of imminent alien attack, it is very important to flee heavily populated areas as quickly as possible. The risk of being abducted and converted into hideous space mutant zombies is very high in densely populated areas.
Failing that, be sure to barricade yourself into your home using whatever is available, such as large pieces of furniture, like a couch. While it is highly likely that you will be converted into a mindless horror by the alien gas drones released by the mothership, the act of barricading yourself inside your apartment contains the risk you pose to those better able to flee the scene.
For those able to flee effectively: Be sure to assist other refugees as best you are able, as the more humans who survive the initial wave, the better humanity's chances of fighting off the cosmic invaders. Be sure to keep a low visible profile while escaping, to avoid attracting the attention of hunter-seeker hybrids, and to spread the word about the alien invasion to those that did not hear the evacuation siren.
For those doomed to die horrible deaths locked inside their houses, we remind you not to turn on your computers, telelvisions, or other personal electronic devices as these are all vehicles used to send instructions to zombified humans by the alien oppressors. In fact, stay out of sight and as low to the ground as possible to avoid exposure to the zombification gas, and disable all personal electronic devices you might be carrying. Our researchers tell us that muscle memory to answer phonecalls is very much present in zombified humans, and that the alien oppressors use this to thier advantage. To do your part in resistence up to the bitter end, disable all such devices while you are still consciously able to do so.
For all persons, regardless, we remind you that as little as 17 to 112 seconds is all that it takes for the mothership to program zombified humans, and that these zombies often attempt to attack police and rescue personel. Fully actuallized zombies have been known to posess powerful psionic attacks, so be careful!