Use Save-As to save your document itself as a template (.DOTM, not .DOCX). The "former" template has merged into your existing document. One way to see is to hit SHIFT-F1, and see the Reveal Formatting pane -- check the box that says "Distinguish Style Source" and you will see what has been added as a style, and what was direct formatted. Using "Draft" View will also show Style choices in the left column.
If it appears that the text has been formatted directly, then you can right-click it, choose the "Styles" drop-down, and then choose "Create A Style" from below those options. Name the style based on how you plan to use it.
After you have extracted all the formatting information and turned it into style-based, not direct, delete any text you don't want to appear as part of the template. This may mean ctrl-A, Delete (delete all of it), and that's ok. You can see that your new styles are still there.
Use Save-As to save your document itself as a template (.DOTM, not .DOCX). (Don't make it normal.dot or normal.dotm -- give it a new name)
To test it, close out of word, re-open it, and open a new document based on that style. (You can start a blank or existing document, and then in File, Options, Add-Ins, choose Templates, and you can then attach the template you just made, and it will apply your formatting choices (if you choose to allow instant updates).
I hope this helped!