this is the result
ok so here we go… first i want to make clear this is NOT the best solution 
i made a struct which holds the item because i was too lazy to create a proper data table for it 
this will be our inventory ActorComponent
PickUp is the Interface Event
this is his very basic interface
the widget inventory itself
the inventory slot widget
this is the item actor, sorry for my laziness 
the item struct, which should be a data table
the item slot struct, which can be left if better invented
basic sprite material
and here is the sort function, if you drop a item it will resort the array…
this is a very very basic inventory and can be done much better… the calls for materials on the slots to update is not the best practice but i am sorry i can not spend more time with it… have too much work to do at the moment… but i hope some points of it can be a starting point to a real inventory
the resort function can be left out, if you like it just plug it in as seen in the screenshots… and it would be good if you make a data table to hold all infos, then you can leave the material sets out… which i would have done if i have more time…
cheers 
p.s. if you have questions feel free to write me