The key to finnishing a doctorate is understanding expectations, having a gameplan, reaching out for help when you need it, never procrastinating, and GRIT.
Life will get in the way. things will come up. If you stay focused, and know that life will continue to throw things at you, you can get finnished.
Become very familiar with all your departmental and university guidelines, especially timelines, committee expectations, thesis content, formatting, and submission procedures.
Your dissertation itself will potentially include five chapters. It will begin with an introductory chapter discussing the issues on which your topic is focused and the approach you plan to use to address the "problem". The second chapter will contain a literature review, discussing in great detail the existing "body of knowledge" on this topic; it will also include the "gaps" -- the gaps are where your own idea(s) might fit into the bigger picture, and why you think this "gap" needs to be addressed/researched. Next is a chapter on methodology. What is your research question(s), and (possibly) your hypotheses? What is your research plan? What kinds of statistical tools might you be needing to use? Those three Chapters are usually completed and submitted to your committee for review before you collect any data. Your proposal defense will rest on those three chapters. It is very important that they are concise yet comprehensive.
Once approved, the work really begins. It is up to you to conduct the research and obtain IRB approval (as needed). It is up to you to follow your proposal plan. It is up to you to analyze any data collected, and determine the findings.
Then you write them up in a "Results/Findings" chapter, following it with a conclusion/recommendations chapter, in which you summarize the findings of the research and its implications for future study.
WRITE or READ Every day until you are done.
Even if you only write for 15 minutes, do it. You may not keep everything you write, but it will keep you in the habit of writing IF you write.