I had given up on this and switched to a different header, but the instructions definitely didn't work. Here is the file structure in my child theme:
[root@moriarty amd]# tree
.
├── functions.php
├── screenshot.jpg
├── style.css
└── templates
├── fullwidth.php
└── header
├── header-style-test.jpg
└── header-style-test.php
The child theme is active, but going to "Header Main" lists only the headers in dukamarket