Hockey Roller Blades Hockey Roller Blades, Wheel Attaching Please HElp!?

Hockey Roller Blades, wheel attaching Please HElp!? - hockey roller blades

I try to change the wheels inside to the outside, but do not come with a piece of metal center. I was told that this piece of outdoor wheels can be transplanted, but I'm having trouble sorting it out. Are there any instructions to the wheels? I need more parts?