How Can I Create Automatically Numbered Headings In Microsoft Word

1. First heading

1.1. First sub-heading

1.2. Second sub-heading

2. Second heading

2.1. More sub-headings

2.2. Etc…

I want Word to add the number automatically so that it is adjusted if I add headings later. I do know that there is the numbering option if I modify the headings styles BUT it doesn’t work the way it should! Word does add the numbers automatically but the above headlines are unfortunately numbered like this:

1. First heading

2. First sub-heading

3. Second sub-heading

4. Second heading

5. More sub-headings

6. Etc…

So now you know the problem that I have :( How can I fix this? How can I get Word to number sub-headings in a way that considers the parent heading number? I hope that somebody can help me… Thanks in advance!