To use the single product submission, you have to create google API credentials.
1. Go to this link https://code.google.com/apis/console
2. Create project
3. Active Content API for Shopping.
4. Create OAuth 2.0 client ID and Client secret
5. Create google merchant account from here https://www.google.com/retail/merchant-center/ and verify your website and collect your google merchant account ID.
6. Configure your shipping information according your selected country from your google merchant account settings option.
7. Back wp-admin Products->WooGoo->settings fill the form required and save changes.
8. Now back your products list and click the add button from your chosen product row. It you redirect you to the single product submission form and click the ‘here’ button for getting google access token.
9. Now from the single product tab you can submit your product to google merchant center.
More details you can check the video tutorial https://youtu.be/ZAskOIV6tHk
Again if you get any problem please give your site credential i will configure your settings.
You know English is not my first language so extremely sorry for my grammatical mistake and spell.