You have to set up a multilevel list of bullets with the desired formatting for each level; read the article for which Charles has provided a link.

As you have alrerady found, you can use Alt+Shift+Left arrow/Right arrow to change numbering levels. If you assign paragraph styles to numbering levels (as recommended in the article), you can apply a style to get the numbering level you want.

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Stefan Blom
Microsoft Word MVP

Microsoft 365 apps for business
Windows 11 Professional