DO it just this way. Second for WindowMaker. You can study the options, but for me the two most important are the directory where WindowMaker will be installed and whether you want graphical special features. I was concerned that I'd not be able to uninstall WindowMaker, so I changed the prefix. I also enabled animations.
Defaults is a directory with the four major WM configuration files.
WMState governs the dock. WM automatically configures that. WindowMaker is important, especially the first line about pixmap path. If you don't set that correctly, nothing will work right. You can edit this to assign icons to specific programs.