The one thing to know about Blogger
Blogger themes offer different gadget areas. The available width is set by the theme, so choose the widget layout after deciding where the gadget will live.
Where reviews belong on a Blogger site
A sidebar or footer suits a compact badge. For a wider carousel or grid, add the gadget to a full-width section supported by the theme.
Full-width sections suit carousel and grid layouts; narrow areas suit a badge.
Reviews and search results
The widget outputs review schema markup automatically. Whether Google shows a star rating depends on what the reviews are attached to — worth reading before you expect stars, because for a business reviewing itself the answer is usually no.
What does help either way: reviews on the page are content, and a page that answers what customers actually say is a page people stay on.