I am currently starting a new project examining the construction of forts in the British North American colonies between 1689 and 1715 and I am interested in learning about the actual process of fort building, which was so extensive across early modern Europe. I'm interested in questions like: How did engineers learn to build forts? How did they recruit the labor necessary? Who labored? How did engineers and other officers acquire the necessary materials to build forts? Any replies, including those with sources, primary or secondary, would be appreciated. Thanks!