how to make objects collide and something happen?

hey everybody, I'm making a game where the character swings a sword. I am fairly new to unity and have read all the tutorials but i can't figure this out - when the character swings a sword at a box i want it to be destroyed. how can i do this? i have a "box destroyed" object and i want this to replace the regular box once the sword hits it. somebody help plz!

add a collider to your box and check it's "is trigger" property. create a script like this

OnTriggerEnter (other:collider)
{
if (other.name=="sword")
{
Instantiate (dsbox);
Destroy(this.gameObject);
}
}

you should define a variable dsbox on top of your script and drag your destroyed box object on to it in the inspector.