How to reference a class that implements interface in variables

Hi, I am a complete beginner with unreal engine and I wanted to make a menu like that:
image
Basically it just loads a map of Strings and Blueprint interfaces that i created. The interface has just one function - OnInteractio which is supposed to be called when i click enter on the selected option.

I also created blueprint classes(that inherits from just object and implements my interface), but I can neither drag and drop it to the variable or choose it.

Maybe there is better approach to doing that, if so, I can change it, but I’d like know how to reference class that implements interface.

Thanks in advance