They needed to make thorough preparations, lots  of weapons and ammunition, lots of food, specialist engineers with catapults to smash their  way in or miners to dig their way underneath.

他们需要做好充分的准备，准备大量的武器和弹药、大量的食物、专业工程师用弹射器砸开通道，或者安排矿工在下面挖通道。