You hid yourself from horrifying monsters and now you have to beat their attacks, shooting from your shelter. After each attack you have 12 hours to repair barricades and make a search of survived people and weapons. Chose how much time you want to spend on this and that, taking your damage into account (it will be shown to you in numbers at the end of every attack). Keep in mind that it is not so save to make a search - it can end with lost of your people sometimes. Hold out as long as you can in The Last Stand, protect yourself from zombies and make a strong defense of your base.