[Edi]

All attacks a unit makes are targeted at the same square. If one attack kills the target, the other attacks are spread out to other targets in the same square until none are left or the unit runs out of attacks.

The only exception is when a unit has quickness in effect, in which case the second set of attacks can be targeted at a different square and then the paragraph above applies to that set of attacks.

On defense they work exactly the same as all other weapons, adding their defense value to the unit and allowing an attempt to repel. For specifics on that, consult your manual.