A* PathFinding Radius sphere

Im using Arongrandbergs A* PathFinding Tool and this is what im trying to do.

Ok so im trying to make it so that the seeker does not automaticlly go after the target, but instead waits for the target to enter a raduis of "what ever amount" and then start caculating a path to that object. Is their a place where i can start to look for help on scripting this, the arongrandberg website is down and i dont know where else to look.

You'll need to use `Vector3.Distance`.

There is a wealth of information about it (and every other basic concept) in the manual.