Hello,
You’re welcome!
1. http://prntscr.com/ic9twj
2. Copy xstore/woocommerce/single-product/related.php file into child theme and do the necessary changes http://prntscr.com/ic9w82
3. Please read how to create variable prodiuct – https://docs.woocommerce.com/document/variable-product/
Feel free to ask if you have any other questions.
Regards