OverLap sphere usage?

Unity Engine
1

How do I use it? I need to know when it is hit and the objects that hit it.

2 
var colliders : Collider[] = Physics.OverlapSphere (transform.position, 3);
    
    for (var hit in colliders) {
        if (!hit)
            continue;
        
        // Do something
    }

A bit modified from the manual, just search for overlapsphere.