Attractor (value)

hi…

i am trying to use this node, and i have a question.
i have understanted how the node work: i put a determinat input in the node and it give me the output that is modified, but i dont understand how link the node attractor with a second object, and use this second object like the thing on wich the imput must be modified. exemp: tha the imput like a spread of box tourn around of one sphere.

thanks to the help