there are so many ways to do it, that it would be very difficult to pinpoint a tutorial that is “right” for everyone.
it highly depends on your usage of it.
There are several question you should ask yourself about the usage of your inventory:
Do you want search functions? do you want sorting filters? do you have stackable items?
Randomized stats? enchantments and/or other effects for items the player can add?
the list goes on and on.
for some usages a simple array could do and for others (with stacks and filters) a deep structure is preferred.
So yeah, think about what you want to do with it, what it needs to accomplish and start working out your structure (i started on pan&paper to theorycraft how i want to structure my database for Görtan).
on how to use dynamic children for structures, you´ll find stuff here on the forum and the wiki, but maybe this topic here might be of interest for you:
there is one thing i can recommend for almost any inventory, and that it should have a mother variable for easy saving. Like Inventory.items and then stuff like inventory.items.count inventory.items.ATK and so on. Everything you want under the mother variable (inventory in this example) so that you can save the inventory as a json string and parse it back later.