This is a lethal trap, never leave this one unattended unless you absolutely have no other choice!!!
The horizontal spear trap is not for the novice trapper, it requires a lot of work and preperation.
However, the rewards can be huge if you are able to catch bigger animals like boar or deer.
You'll need to set up the 4 sticks very deeply in the ground, so it can withstand the force of the swinging arm, the impact and the force it takes when sitting idle. Alternatively, you can use two standing trees that are very close together and tie the arm to them.
In this picture, only one spike is attached to the arm, but you can use more if you prefer that.
For every spike you'll need to cut notches in either the spike or the arm so they fit together snugly. My advice is to cut the arm.
As trigger, you see a standing pole and a horizontal one. On the end of that one is a small notch in which your catch-stick rests. The toggle is tied to the rope, goes around the horizontal stick.
When an animal touches the wire, the toggle pushes the catch-stick free and all force of the swinging arm is released.
Practice, but respect the local laws!!!