Is it possible to add text to a style?

I found this MS Word tip about adding text to a style:

http://wordtipsandtricks.com/2015/06/28/add-text-to-a-style/

I am using the desktop version of MS Word 2016 on a Windows 10 computer. I create a new style, and choose:

• Modify
• Format
• Numbering

Once I'm in the Numbering dialog box, I choose:

• None
• Define New Number Format

I'm able to enter text in the "Number format:" dialog box, but as soon as I delete the grayed-out number field (the default value is "1"), the OK dialog box becomes grayed out.

Essentially, as soon as the automatic numbering is removed from the "Number format:" field, it becomes impossible to save. This renders the "trick" impossible to complete as shown in the video.

Am I missing something? Is there a way to create a style using text instead of an automatic number?

I'd like to create a "Note:" style where "Note:" appears automatically.