First, log in to Review Grower, go to Widgets, then Embed Code, then click Copy Code.
Then, navigate to the page where you want your reviews to appear in your Squaredspace website editor. Click the Plus (+) button on the area where you want to embed the widget, go to Embed, then Embed Data, then paste the code. Click Back and then click outside the embed popup to exit the popup. At the top left, click Done, then click Save.
Below is a short video showing the entire process: