Step 1: Remove the rubber bands, and lay out all five panels in order. (Note we pay careful attention to use enough heat to just nearly cut out each piece, without actually cutting out each piece and risking losing any of the necessary pieces. If you cannot easily pop a piece out of its panel, carefully take an x-acto knife or small blade, and gently cut against the score lines on the back of the panel to assist in removing each piece.)

Step 2: Remove the two arm pieces and the basket on panel 2. Place the two arm pieces together, and fit the basket into the notches (labeled 12). If needed, stand the arm upright and use down-ward pressure to ensure the basket is securely attached to the arm.

Step 3: Remove the pieces left on panel 2 that make up the releasing mechanism. With the numbers facing you, and the hole (labeled 1) farthest from you, fit the hole (labeled 2) in-between the holes (labeled 1 and 3), using the small rectangle piece on panel 1, inserting it through all three layers.

Step 4: Remove the lever piece from panel 1 and insert the corresponding 0’s. Insert the remaining two pieces into their corresponding numbers (13 into 13 and 14 into 14) and the releasing mechanism is completed. ( Note the center latching piece should have the ledge facing to the right towards numbers 10 and 11)

Step 5: Remove the main body pieces on panel 1 and 3. With the numbers facing out, align the two rectangular braces so they match the holes on the larger side pieces. Then insert the two cross beams, with the larger one on top. While glue is not necessary, feel free to apply a drop of glue at these intersections.

Step 6: Insert the latching assembly into the holes on the skinny end of the side piece. Then attach the second side piece to complete the main structure. This will take a little work to ensure all of the pieces are lined up correctly. Remember, they are designed to fit tightly together. If needed, a few gentle taps with the handle of a butter knife can get the pieces to connect completely. Once your main assembly is complete, it should fit onto the base plate. Again while glue is not necessary, feel free to apply a drop of glue at these intersections.

Step 7: String the rubber bands through the oval holes. 

Step 8: Secure each end of the rubber bands around the rectangular knobs on the front of the assembly.

Step 9: Insert the catapult arm above the rubber bands, with the notches on the arm facing downward. Fit the top rubber band in the top notch, and the bottom rubber band in the bottom notch, then pull back slightly, and pry the bottom of the arm under the bottom crossbeam.

Step 10: Remove all the remaining pieces. Insert each of the 4 fence sidings into their corresponding slots. You can use a flat surface to lie the base piece on and you can use down-ward pressure to ensure the sides are securely inserted into the base, all while making sure the base remains flat. 

 Step 11: Insert each of the cut out circles into one another in order to form your ammunition.

Your desktop catapult is now complete! To operate, gently pull the arm down until it rests in the latching mechanism, and use your finger to engage the latch. Load a piece of ammunition (one of the wooden balls included in the kit, a marshmallow, or any other small projectile) into the basket, aim, and press the release lever to fire your catapult.