How it (probably) works:
The blade goes on the spigot in the middle, and it appears there are some additional size adaptors in the box. Top right there is a tooth stop to register each tooth at a time and it has a corresponding mounting point at the top left. Slightly puzzled that these are painted not machined surfaces.
A long thin object in the box with machined bars at each end pivots in the machined holes at the top of the device. I believe this bar is in fact bolted to the grinder and the rest of it with saw blade attached is what pivots to pass the a tooth over the grinding wheel.
The L shaped item in the box probably fits on the machined bar above and the adjusting screws bear against the body to control swing in each direction.
But it would be nice to see instructions and see it in action.