Word 2010 and 2013 take most of the effort out of creating and maintaining a table of contents. With Word, you don't need to format the table by hand or track down the page number for each section or chapter. Word's Table of Contents feature isn't magic, however -- for it figure out what you want in the table, you first need to assign heading styles to the headings in your document that you want included.
Select the first heading in your document that you want to appear in the table of contents, such as "Chapter 1" in a novel. Right-click Heading 1 in the Styles section of the Home tab and select Update Heading 1 to Match Selection.
Select each other top-tier heading in your text -- "Chapter 2," "Chapter 3" and so on -- and click Heading 1 to apply the style. Because you updated the Heading 1 style to match your first selection, choosing the style won't alter how your text looks.
Repeat the process thus far with any secondary headings, such as sections in chapters, using the Heading 2 style. For further subdivisions, repeat using Heading 3 and so on.
Place the cursor in the text where you want to insert the table of contents. On the References tab, click Table of Contents and pick one of the Automatic Table styles. In Word 2010 and 2013, the only difference between Automatic Table 1 and Automatic Table 2 is whether the title reads "Contents" or "Table of Contents." You can also edit the title by hand later.
If you're happy with how the table looks, you can stop here. Otherwise, it's time to customize the table's style.
Choose Custom Table of Contents in the Table of Contents menu. The first few options deal with the table's numbering -- you can turn off page numbers, set whether the numbers align to the right or pick a new Tab Leader to change the row of dots leading to the page number.
Raise the Show Levels number to match the number of heading styles you used. There's no harm in leaving it at 3 even if you only have one or two heading styles.
Pick a preset style for the table from the Formats menu, or choose From Template and press Modify to open the Style dialog box and customize each tier of the table manually. In the Style dialog box, TOC 1 refers to the style for Heading 1 entries, TOC 2 for Heading 2, and so on. Press Modify to change the font, text size, alignment and other style options.
Click OK and choose Yes to replace the automatic table of contents with your custom version.
Press the Update Table button on the References tab or directly above the table of contents to rebuild the table. Update your table any time you make changes to your document. Choose Update Page Numbers Only, or choose Update Entire Table to update both page numbers and heading text.