This is yet another reason to use MS Word Styles and Templates.
Doing so gives you two major benefits:
First, if you assign Heading Tags as you go, it helps you to organize your material.
Press the tiny down-arrow at the right end of the box, to see available Styles.
Assign Heading 1 (or Heading 2 or Heading 3, etc.) to paragraph titles you want to appear in your Table of Contents.
Go to the place where you want your Table of Contents to be displayed.
(Most books put the TOC at the beginning of the book, but some Kindle authors prefer to put it at the end of the book to make more room for a Sample in the front.)
From the Ribbon Menu at the top of the MS Word 2010 screen, choose:
References | Table of Contents
From the Table of Contents Drop Down Menu, click "Insert Table of Contents".
A Selection Box appears to let you choose exactly what you want (for Kindle, un-tick the page numbers box)... then your Table of Contents is built and appears at the point you chose.
That's all there is to it.
If you later make any changes that could affect page numbers, come back to your Table of Contents, highlight it, then press the "Update Fields" key, F9, to have MS Word completely rebuild your TOC.
To find more on this or any subject about publishing to the Kindle, scroll to the bottom of any page to see a list of articles, then search with CTRL-F.
Second, with Heading Tags already assigned, you can build your Table of Contents in just minutes.
To assign Heading Tags, open the Styles box this way:
From any Menu, press the key combination CTRL-SHIFT-S.
A small box named "Apply Styles" will appear towards the upper left of your Page.