The one thing to know about Drupal
Filtered text formats can remove script tags. Use Full HTML for the block and clear Drupal caches after changing its placement.
Where reviews belong on a Drupal site
Use Block layout to place reviews in the content region, a sidebar, or the footer. Visibility rules let you limit the block to selected paths without changing the widget.
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.