Before I got stuck, I added these to the wcp plugin folder (didn’t know if there was a way to connect the plugin in function.php)
// wcmp data tabs
add_filter( ‘wcmp_product_data_tabs’, [ $this, ‘product_data_tabs’ ]);
//wcmp data panels
add_action( ‘wcmp_product_tabs_content’, [ $this, ‘product_data_panels’ ], 10, 3 );
//wcmp save
add_action( ‘wcmp_process_product_object’, [ $this, ‘save_actions’ ], 10, 2 );