. He first created a paper template and used this template to mark the cut lines on the copper. You can see the template in the picture below.
He then put the 4 pieces on the cupola roof and bent the seems down to lock them together, he did not fold the bottom edge under the roof yet. He then pulled the 4 pieces off together and placed them upside down in a large box and soldered the top and bottom corners to hold it together.
A bead of outdoor caulk was placed in each seam for waterproofing. He then placed it back over the roof and finished bending the copper down and under the roof base. Finally it was nailed in place under the roof base where it won't be seen.
Here are a few more pictures: