When you get to the folder with normal.dot in it, navigate from there to your other template. When you click on the document template button and click on attach, you need to find your template. Anything listed in that dialog before you push the Attach button is irrelevant.

Did you save Doc A as a template? You have to tell Word you want a template and not a document when saving.

If this is difficult, use the Organizer. That, too, will require that you find your new template or the old Doc A document so you can list the styles.