You should receive 26 balsa fins and 2 pieces of acrylic. Bulb is not included, and any oversized bulbs will likely not fit the shade. Only 20 fins are needed, 6 are extras in case some break over time.
First, remove the ring on the Regolit lamp.
Place the smaller acrylic ring around the bulb-holder and secure it in place.
NOTE: It is easiest to place the light bulb in the socket at this point!
To start, slot two fins into the small ring on opposite sides.
Now slide those fins into the larger ring. Make sure that the number of slots between the fins on the upper ring matches the number of slots between the fins on the lower ring as well.
Repeat the process for the remaining fins. The shade will become more stable the more fins you add.
You can see here how it is a little harder to reach in and place the light bulb after assembly. It is not impossible, but since the fins are fragile it's easiest to place the bulb in before assembly.
That's it! Enjoy your new lamp shade, and contact me if you have any questions or concerns.