New Gui 4.6 - How to use new GUI for inventory system

I am trying to make an inventory system which holds a certain number of items for different storage objects. I know how to create one using arrays ( This question is not about how to create a system - Its how to use new GUI to do so)

So I want to ask, how can I use the new GUI to accomplish this. How would I go around making a table of items, or even how would I script (C#) the adding of array of items images into a table.

I'm finding learning this new GUI a bit daunting at the moment, since I am used to a code approach more and I cant find how to code it, then again I only messed around with it for 2 hours.

Please help, Thanks