Reading Purchase Information and Completing a Purchase

How the estruta works

Hello, I need to help, how should I make the blueprint work and I have no idea what I’m doing or what works.
I got to that point with tutorials and tips from other people, but I do not know if it’s right.

My first question is what is reserved for the item being sold?
is the id that generated when I generated the value or the name of the product or is it all together, I have no idea.

From now on, it is a structure that is literal or works at least. following as images.

Both functions can be used at different times or not, in case you read the product and finalize the product.

in case I just click the buttons and nothing happens.

probably not so is the structure to much lost in that question.

Thank you, help me.