In RepU, open your widget, choose light or dark and left or right, then click Copy next to the embed snippet.
Open each .html file and paste your code just before the closing </body> tag. If your site uses a shared footer file, paste it there once instead.
Upload your updated files to your host, then open your live site to see your Google reviews.
Check your live site in a private window, not the editor or preview. A domain-locked widget only shows on your own domain.
Make sure every page has the script, and that you uploaded the updated files. Opening files straight from your computer can block the script, so check the live site.