If you do go with the 3-speed fan used here, look ahead in instructions to see where the switch gets positioned, then attach fan appropriately to the bracket/shroud plate.

Note direction fan is attached. The side with cable lead-in to motor, (and usually the only label or fancier of the two hub labels), that side faces inward towards the heat sink, and the bracket/shroud plate.

Don't freak out if you think you can't fish the cable through the shroud the right way. You can pass the whole fan through the shroud hole on the 45º.