The one thing to know about Weebly
Weebly is effectively in maintenance under Square, so treat it as a platform you are supporting rather than building on. The embed works fine; just do not expect the platform to change around it.
Where reviews belong in a Weebly site
An Embed Code element dragged onto the page.
Full-width sections suit carousel and grid layouts; sidebars and narrow columns suit a badge. Floating badges can be restricted to particular pages and to desktop or mobile.
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.