The question explains it all , but i want a detailed explanation
basically a Vector3(0,0,0) is a position on the 3D space first 0 is the X axis, second one is Y axis and third 0 is Z axis.
and you can use it to set some GameObject over a exact position or even to move something over time on the desire axis only, using “Update method” for example.
the above explanation also works for “Rotation” and “Scale”.
I hope these videos can help you