@ntinos83
To know, where and how to implement the shown code depends on your project’s and DB - structure.
Your DBs are already prepared?
Do you already use some code?
Do you create a totaly custom Shop, or do you use wix-stores-app?
Do you use DATASETS?
Do you use dynamic pages?
There are so many unknown informations, so it makes almost impossible to give you a right answer.
Elaborate AMD describe a little bit your project-setup, which Elements are used and which DBs are included and how everything is connected with each other.
It is very simple…
The more INPUT → The more OUTPUT.
If you worked without code until this momentan, then first activate DEV-MODE in your Wix-Editor.