I write my dissertation work in plain text using formatting language to output the document the way I want it to look. I highly recommend you do the same as this is the best way to manage large documents, in my humble opinion of course.
This will save you the headache of formatting problems that emerge with using writing software.
I will be providing a webinar on how to write and format in plain text on October 20th from 1-2pm you can sign up here https://my.cgu.edu/preparing-future-faculty/home/events/.
I provide this Word template for you to use in the meantime, and in case you are insistent on using Word over plain text. I am not an expert in Word, nor do I want to be. If you need help with formatting issues in Word you can contact the CGU Writing Center or attend workshops in the DDL.