In RepU, open your widget, choose light or dark and left or right, then click Copy next to the embed snippet.
In Jimdo Creator, click into your footer area that appears on every page. Add an element, choose Widget / HTML, and paste your code.
Click Save, 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.
Free Jimdo plans cannot add HTML. The newer Jimdo Website Builder does not support custom code, so this works on Jimdo Creator only.