Hello @nataliyag2,
Thank you for your inquiry. Unfortunately, our theme does not have any influence on the WooCommerce-related products feature. We suggest that you read and follow the instructions in the following threads:
https://wordpress.org/support/topic/show-related-products-based-on-tags-only/
https://wordpress.org/support/topic/woocommerce-related-products-by-tags/
https://stackoverflow.com/questions/31122389/woocommerce-related-products-by-tags-and-categories
Alternatively, you may wish to contact the WooCommerce support team for further assistance.
Best Regards,
8Theme’s Team