I need some help with conversion of DocBook files to Microsoft Word files.
Do I need an XSL file for the transformation?
Yes, you do need an XSL file. You can get XSL files for DocBook from the free DocBook XML distribution. Then, you run a free XSLT transformer such as Saxon. If you run Saxon from a command line, you give it the name of your DocBook file, and the name of one of the stylesheets, and it will transform your file according to the rules in the stylesheet.
What you need to do to transform to Word, is to pick the right stylesheet.
From DocBook XSL: The Complete Guide, here are three possibilities:
And I have one of my own: