Gazette Theme: No Customizer option to set featured tag

I’m using the Gazette theme by Automattic and have added ‘featured’ to the tag for six posts on artrelish.com, but they are not showing up in the big beautiful grid as in the theme demo.

I see I’m meant to add the ‘featured’ tag in the site customizer, but there’s no option related to tags under the customizer.

The only options in customizer are:
site identity, colors, header image, menus, widgets, static front page, theme options.

Maybe self-hosted Gazette is entirely different than the same theme WordPress.com-hosted?

Help? Thanks.