Danke und gute Nacht,
Step 1: The Frame and Trigger.
Picture 1: This will be the right side of the frame.
Pictures 2-5: Close-ups of the right side of the frame.
Picture 6: Grab these, they will hold the mechanism later.
Picture 7: Put the pieces here.
Picture 8: Put two spacers on the upper piece.
Picture 9: Add the cog and two more spacers.
Picture 10: Make the trigger.
Picture 11: Be sure you do not add green rods on the sides.
Picture 12: Now slide it on to the blue rod (The blue rod will be slid into the half circle). Be sure that you put green rods into the holes.
Picture 13: Add two rods to these spots and add a rubber band to the rods.
Picture 14: The left side.
Pictures 14-17 : Eh, close-ups of the left side. Exactly the same as the right side, but without the orange rods sticking up.
Pictures 18-23: Clamp the two sides together.
Picture 24: Now add a spacer and a connector to each blue rod.
Yay, it is almost done.
Step 2: The "Barrel"
Just follow the pictures and attach it as shown.
To load, you hook the rubber band on to the barrel, then to the cog, then pull back on the cog. Repeat until you have attached 8 rubber bands. Pull the trigger to fire.