The answer to 'how to kill stink bug' is to use an insecticide specifically designed to target stink bugs. Apply the insecticide to areas where you've seen stink bugs, such as around windows, doors, and other entry points. Be sure to follow the instructions on the insecticide label carefully, including any safety precautions.
For a more natural approach, you can also try using essential oils like peppermint or lemongrass, which can help repel stink bugs. Regularly vacuuming and sealing up cracks and crevices in your home can also make it less inviting for stink bugs to enter.