Step 4: Under the roof
Now let's cut out the holes on the upper layer of the roof. The holes near the center fold line shall best be aligned with those on the inner layer for ease of connection. Those holes shall drift away from the center fold line for just a bit due to the paper thickness. Then, use the solar panel prepared in the last step to measure the separation between the two holes on the upper layer of the roof. Holes shall be directly under the first and last solar cell. In the photo attached, you can see that there is a shaded region between the 2 holes on one side of the upper roof. That shaded region corresponds to the second hole of the lower layer. You can then cut out a strip of copper tape of around 2-3 mm wide and connect the holes at the sides and at the shaded regions as shown in the photo. This can then be glued onto the lower roof with some random glue. Instant glue will do this just as well but emer's glue will certainly do a better job.