Target Obj
Specify the target object, owner's position will be dependent on the target;
Affect
These options decide which components of owner are affected and how should it be affected.
"+X" means it will takes the target position's X component, and apply on owner; "-X" means it will applies the negated target position to owner;
e.g.: if you only switch on "+X" & "+Z", then the owner will take target's position's X & Z component, and ignore Y component from target completely.
Offset
The owner doesn't have to be strictly has the same value with the target;
if "Offset" is enabled, then an extra Vector3 value is added to result vector at last;
You could use offset to make the owner to "keep a distance" with the target;
Space Mapping
"Target Space" decides how to extract source vector from target, "world" means using transform.position, "self" means using transform.localPosition;
"Owner Space" decides how to apply result vector to owner, "world" means using transform.position, "self" means using transform.localPosition;