The vertical rod in the middle piece is rod A with (in order from bottom to top) rod B, C, D, E, and F. Mark with a sharpie these next spots. Mark a spot that is 2cm from the bottom, 4cm from the bottom, 6cm from the bottom, 8cm from the bottom, 9½cm from the bottom, and 11cm from the bottom. Rod B will go on the 2cm mark, rod C will go on the 4cm mark, rod D will go on the 6cm mark, rod E will go on the 9½cm mark, and rod F will go onto the 11cm mark. NOTHING GOES ON THE 8cm MARK YET.
The 2 parts on the outside are the parts G, H, and I. The vertical rods in those are rods G. On that rod make marks that are 13mm, and 3cm away from the bottom of rod G. Rod H will go onto the 13mm mark and rod I will go on the 3cm mark.
Once you have placed the rods on the right marks, glue them down.
Now take part A (the vertical rod with the 5 others on it) and the two G assemblies (Rods G with the two other rods on them). Take one G assembly and, on the 8cm mark, glue the bottom of rod G at a 45-degree angle from rod A. Do the same with the other part G on the other side.