Hello,
Please watch this video – https://youtu.be/XO-PDvhPypc
Size guide image you can upload in Theme Options > Single Product page > Page Layout http://prntscr.com/oqu5r2 or for a product individually via [8theme] Product Options http://prntscr.com/oqu5u8
http://prntscr.com/oqu5yk = http://prntscr.com/oqu648 + http://prntscr.com/oqu66u ( https://youtu.be/1Nu49dskD1Q https://xstore.helpscoutdocs.com/article/101-wpbakery-page-builder ) + http://prntscr.com/oqu6qf http://prntscr.com/oqu6uh https://docs.woocommerce.com/document/related-products-up-sells-and-cross-sells/
Also, https://youtu.be/4SfPPuwPCVI
Feel free to ask if you have any other questions.
Regards