Product sorting

Hello! (again me)

So, I found yet another detail that probably can be fixed, but I can’t seem to find anywhere.

The sorting of products, according to sizes, and not apparently by the order I made them.

I installed a plugin to sort almost everything in WordPress, and it even lists Sunshine Product Categories. But not products.

How can this be done?

Thank you again!

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