Construct Object from an Array when increasing array size

I have this situation:

I have an Actor BP_Container, which contains an array of actors BP_Box, lets simply call it BoxesArray.

What I want is that, when I drag an instance of BP_Container and I start to increase the size of the array, instead of having each index showing up as “None”, it should automatically create an instance of BP_Box and add it to the array.

Basically, instead of having to manually add each BP_Box inside the editor viewport and then add each one of them to the array contained inside BP_Container, I want these BP_Box to be dynamically created and added in order to automate this process. Obviously, I still need to be able to have full control over each BP_Box object (moving them around, changing their size, their variables etc).

I assume I need to work on the construction script to do this, but the best I could come up with was this and it doesn’t work:

What does the error say?

Cannot construct object of type BP_Box

I created BP_Box as a brand new blueprint (not as a blueprint child of a C++ class), I’m just using it for prototyping some stuff. There’s nothing inside BP_Box.

And I actually get the same error if I try to call construct… on anything really. I just tried to call construct for a completely different class and I still get the same error