You can substitute this card for any 1 Fusion Material Monster, but the other Fusion Material Monster(s) must be correct. You can Tribute Fusion Material Monsters on the field, including this face-up card; Special Summon 1 corresponding LIGHT Fusion Monster from your Extra Deck.
How to Get
Tributes for cost / Tributes itself for cost
Fusion Substitute Monster / Special Summons from your Extra Deck