On the 18th of Felsite, an ambush arrives in the east, of goblin corpses lead by a dwarf corpse, but as those in the west, they're stymied by our great walls. If we had fortifications, I'd let the military amuse themselves shooting, but we do not. I'd let them stride out and strike, but I still am unable to locate the lever control.
I would NOT advise the use of the military against undead. They're not in any shape to do it, and the melee guys will just get slaughtered. Again. Better to conscript some masons and build another tower on the west so we can use archers on that side. On the eastern side, the two towers near the gates will let you shoot down some of them at least, especially if you add another floor or two. There's also McDonald's tower right at the north of the fortress which I used to pick off the eastern undead previously. Sending the main militia force will just result in us losing more dwarves we can't afford to lose.
...The current drawbridge controls are on the surface courtyard. On the notes screen my levers are denoted by a red exclamation mark on a purple square (or possibly vice-versa), and you're looking for a cluster of 4 of them...each one is individually labelled. The eastern entrance has two sets of bridges, both of which need to be open in order to have access. Again, however, I really, really, really wouldn't advise it....we lost a
lot of militiadwarves trying to take on undead in melee during my turn, and the average skill of the military has gone down since then.
One solution I'd suggest: Post a marksdwarf squad in each of the two gateway towers (southern one may not be good enough for archers. In that case, put two melee squads in there as backup just in case, and put all marksdwarves in the northern tower). Pull BOTH levers inside the ground floors of said towers to seal them off. Evacuate all civilians to the main fortress and raise the bridge across the moat (part of the same lever cluster). Then set the "crusher" lever to repeat, and open the bridge in the outer wall.
.....If it works, the undead will surge into the fortress to go kill some tables and stuff (might be worth building a couple for them to smash beforehand), and the crusher will smash them while the marksdwarves pick off any stragglers. Remember to turn off the crusher and close the outer gate before allowing any dwarves back in/out of their siege positions.