floor deadning plates.. where should they be fitted?

im just putting the floor mat and the sound isolation back on place
but found those asfalt type of board lying on the garage floor..
i cannot remeber where they should be.. but it seems that they go under the the mat where the drive have its feet
and the oppisitive side too..am I right ?

also.. is it right that the rear part of the floor dont have any isolation at all besides just the floor mat and a thin bitume mat?