Since your product data is already stored on your website, the only thing left to do is to feed that data to Google.
That data is sent to Google in a format known as a Product Feed. That’s where Google Merchant Center comes into play.
Step 1 - Locate your Product Feed URL
In your Shopstar admin area, go to Sales Channels > Product Feeds
You will see a section on the page called "GOOGLE MERCHANT CENTER"
Copy your feed URL, which will look like this: https://example.co.za/facebook_xml_feed
Step 2 - Upload your Feed to Facebook
Sign Up / Login to Google Merchant Center
Add your website (https://www.example.co.za) to Google Merchant Center
Verify the ownership of the domain name (Google Analytics or other methods provided) use the meta tag option during verification and paste the entire <meta tag> into the settings>>general>>custom domain section.
Navigate to 'Products' on the left menu, and click on 'Feeds'.
Under 'Primary Feeds', click on the + icon to add a new feed.
Fill out the basic information under 'basic Information' section and click 'Continue'.
Give your feed a name, such as 'Shopstar Products' or 'My Products'
When selecting the TYPE of feed, select 'Scheduled Fetch' and click 'Continue'.
Under file name, give it a name such as 'My Feed'. You can leave the Frequency, time and timezone as they are.
In the 'FILE URL' field, provide your feed URL from above. There is no username/password.