The Aqua Sphere Alpha Fins (found here) offers unique features; such as having the blade located on top of foot to increase kick efficiency by transferring more power to the blade. This can cause some confusion when wearing the fins for the first time. 

When the fins are worn correctly the curved blade will sit on the outside of your foot, the Aqua Sphere logo will be on top and the stamped fin size on the bottom. The fin should fit snugly to avoid blisters from friction, but not restrict blood-flow or movement. 

For more information on swim fins, read How to Choose Swim Fins.