How do I automatically number headings in Microsoft Word? [duplicate]

Possible Duplicate:
Word: continued title numbering

I have a Microsoft Word document which consists of (more or less) the following heading structure (this is just the heading structure, not the actual content of the document. I have some text bellow each heading):

heading 1
    heading 1.1
    heading 1.2
        heading 1.2.1
        heading 1.2.2
heading 2
    heading 2.1
    heading 2.2
        heading 2.2.1
        heading 2.2.2
    heading 2.3
heading 3
heading 4
    heading 4.1
        heading 4.1.1

etc.

EDIT: headings 1,2,3,4 are of type heading 1, headings 1.x, 2.x, 3.x, 4.x are of type heading 2 and headings 1.x.y, 2.x.y, 3.x.y, 4.x.y are of type heading 3.

I would like to automatically change the text of each heading so that I'll have them all numbered. In the above example I would expect the heading structure to look like this:

1. heading 1
    1.1. heading 1.1
    1.2. heading 1.2
        1.2.1. heading 1.2.1
        1.2.2. heading 1.2.2
2. heading 2
    2.1. heading 2.1
    2.2. heading 2.2
        2.2.1. heading 2.2.1
        2.2.2 heading 2.2.2
    2.3. heading 2.3
3. heading 3
4. heading 4
    4.1. heading 4.1
        4.1.1 heading 4.1.1

How do I do this in Microsoft Word?

Solution 1:

Using Office 2007 goto Paragraph then Multilevel list on the ribbon. You can customise the numbering to what you require under Define New Multilevel List.

You may want to take a look at this video Settings Headings and Numeration [Word 2007-10]