Shipping and box size help.

I am having a difficult time wrapping my head about how shipping and package sizing works. Are better tutorials?
On product sizing do I put the size of the package or the size of the product?

THanks

Hi,

I think that you should set the size of the package that you'll send to your customer through the shipping company.

Hope this will help you.

But I only have one size option in the shipping plugin.
I find this very confusing...