The "fixed cleats" can be recognized by the 2 concentric circles on the cleats, the "float" cleats SM-SH71 have arrows instead.
The metal bridge with the 2 plastic parts, called "pontoons", must be used.
Road shoes don't have space for recessed cleats in the shoe tread (compared with touring or MTB shoes).
The pontoons enable for more or less safe walking (don't over estimate this) and give extra support or contact surface (stability) when the shoes and cleats have been clicked into the pedals.
