This is a rather awkward way of saying, “These events have symbolic meaning.” A shadow is not the object itself but rather a reflection, an evidence of the nearness of the object. Types or shadows- like animal sacrifice, the brazen serpent, or the Liahona- are not Christ himself, but a reflection of Christ, a representation of the Redeemer.
“All things have their likeness,” Jehovah explained to father Adam, “and all things are created and made to bear record of me, both things which are temporal, and things which are spiritual; things which are in the heavens about and things which are on the earth, and things which are in the earth, and things which are under the earth, both above and beneath: all things bear record of me” (Moses 6:63).