It doesn't help that many of the official Debian wiki pages contradict eachother in what tools to use or how to use them. It took me a long time of plain experimentation to realize that the debian directory contents are mostly agnostic to what tools you're using to build the package itself, and then it's just figuring out which CLI build tools you can figure out how to get to run (for me it was a combination of cowbuilder + pdebuild, and cowbuilder is optional).