You can make a makeshift macadamia nutcracker with a vise grip, an iron bar to set the nut against, and a flat hammer.  Vise grips are common tools available at any hardware store. If you love macadamia nuts and plan to shell them often, it's worth buying a vise grip for this specific purpose (though you'll probably find other uses for it as well). Be sure the hammer has a flat end, rather than a round one. You'll need to exert force evenly on the nutshells. If you don't have an iron bar, any tough, metal surface will do. Other hard surfaces like marble, glass, concrete or wood could get damaged by the pounding, so make sure you're working over metal. Lie it up so that the seam of the nut is facing upward, rather than against the inside of the vise. Set the vise to grip it tightly. Hold the vise handles tightly and make sure you've got a good grip, since you don't want the nut to slip when you bring the hammer down. Try to hit it square on the seam so that it cracks cleanly. Let the hammer bounce back toward you as the nut cracks open.  You may have to try this a couple of times before you learn exactly how much force to exert. Letting the hammer bounce or pull back slightly is important, since it keeps the hammer from smashing the nut inside. The shell will fall away, and the intact nut is now ready to be popped into your mouth or  used in a recipe.

TL;DR in Chinese:
准备工具。 用钳子夹住夏威夷果。 把夹住的坚果按在金属板上。 用锤子敲击夏威夷果。 松开钳子。