You can use the Apply Styles pane (Ctrl+Shift+S) to apply the List Number
style to selected text. Note that you can and should modify the style to
suit your needs. Click the Modify button, and then click Format, Numbering.
Click Define New Number Format. In the "Number format" box, delete the
period. Click OK.
After you have closed the Modify Style dialog box, right-click the numbered
paragraph and then choose Adjust List Indent from the context menu. Clear
the tab stops and indentation. Click OK. If/when you are prompted to update
the style, choose to do so.