How to start heading with 2.1.?

[Kaedro]

Hello everyone,



My document needs to have the following structure:
Chapter 1 - XXXX
1.1. XXXX
1.2. XXXX
Chapter 2 - XXXX
2.1. XXXX
2.2. XXXX
Etc.

When I created the 1.1. there was no problem, I simply wrote "1.1." and Word automatically recognized that it was a heading. But, now that I am on Chapter 2, if I write "2.1." it stays as plain text and is not recognized as a heading.

If I write "2" and then "2.1." it will recognize both as headings, but I do not want "2", I want to start with "2.1."

I would be extremely grateful if anyone could help me.