Hello,
Navigate to Theme Settings > Single Product > Related & Upsells > enable the option Show Related Products.
If you are using a custom layout for a single product page, you can add the product grid or carousel widget in the bottom of the layout and choose the data source “Related Product” .
Here is a screenshot for clarification: https://snipboard.io/xc8l0s.jpg
Further, you can read more about the Layout Builder here: https://xtemos.com/docs-topic/woodmart-woocommerce-layout-builder/
Best Regards,