It isn't a fancy publication and the one in the picture is well worn. There are 79 pages of drawings and notes about how different patterns were marked.
This photo show a page where I try to explain how I divide space up, mark the double lines and then divide and mark double line again. In the Handbook, I used the term 'outlining' for the marking of the second but I think the word 'echo' might better explain how the second line 'echoes' the first. One of the things you have to decide is which side of the first line you wish to mark the echoing line. Mark them all the same... for instance, if you have marked the lines that divide the outer border on the outside when you start, mark all the lines the same on the other sides of the design. But, if you make a mistake, the world won't come to a crashing end.
These pages are about marking motifs and tips for folding paper to make templates.
These pages show how I divide up border for filling with different patterns. The left page shows the basic division of the border space and the right page shows the divided area of the border filled with repeating patterns and motifs.
The Handbook isn't like a book off the shelf at the quilt shop but it seems to get people started and when you've become good at looking closely to Welsh quilts, it'll help you see how the designs were divided up and the patterns were marked.
May the Welsh quilts capture your imagination.