customizing WooCommerce

My client wants to rearrange the order and look of the product page, putting the description below the size, quantity, price, etc. Sounds simple enough, but I know that this is set up with php and css, and I’m not finding where this is set up, or where to customize it. I have tried making simple css changes to the lines in my style.css page, but there is nothing happening.

So I am in search of basic knowledge – if I want to change the php, where do I make the changes? I have added several lines into my functions.php file (child version, of course) but again it’s not doing anything. I’ve rearranged the order of the content-single-product.php file, saved it in the child-theme-directory/woocommerce directory, no change. When I look at the developer tools there’s a table set up somewhere for the size & option boxes, seemingly in woocommerce.css. I added a file by that name to the directory woocommerce in my child-theme directory to make changes, but it is still referring back to the original style sheet. There must be a way to customize this, but I don’t have a firm enough understanding of how WooCommerce interacts with WordPress, how and where the files are that I need to be looking at, how WordPress knows what file to look for, and where to make any changes.

Any help is appreciated, from links to articles to actual code help. The more I understand the basics of how WordPress relates to, in this case WooCommerce, but it could be any plugin or theme, the more I can complete the picture in my head of what I need to be doing.

The page I need help with: [log in to see the link]