
The Bonk can be picked up by reaching for it and pressing the trigger button on your controller. There are 2 handles where you can pick up the Bonk, on the front and on the back of the Bonk. You should now grab the second handle with your other hand. With holding the Bonk in both hands, you can go up to a door and breach it.
You can use the Bonk to open a door regardless of whether it is open or not, but it is of course usually used to open a locked door. When you are standing next to a door, you can slam the Bonk against the door, which will also make a distinctive sound. It usually takes more than 1 hit to open a locked door. The number of times that you need to slam against