Activate the plugin then use the link in the Admin Notice to go to the API Key activation screen.
Enter your API Key and Product ID into the form. The Product ID can be found in the Completed Order email, and in the My Account dashboard under the API Keys tab.
If all the information is correct the API Key will be successfully activated.
The WooCommerce API Manager Product Tabs plugin is automated. Setup the API Products as instructed in the WooCommerce API Manager documentation. The Product edit API tab shown below has only the Changelog page set, so the Changelog content is displayed. If the Documentation page is not set, the Documentation tab will not be displayed.
If both the Changelog and Documentation pages had a value set, and contained content, then that content would be displayed when the corresponding tab is clicked on product page.
Additional tabs are set in the WooCommerce > API Manager > API Doc Tabs section as shown below. When these tabs are set they will appear on the product page.