Uff, i’m currently only on my phone. This is some basic object oriantated programming. You might want to learn about c++ sooner or later (BP don’t replace c++, because they are C++).
An example would be: You have a ThirdPersonCharacterBP. You spawn one when playing. It’s the character you play. You can spawn multiple for multiplayer or enemies.
Same goes for your PuzzleBlock. You have a Blueprint and you need to either place one or more in the scene or spawn them.
Then you need to get a reference to it. Better search google for ‘ue4 get reference’ or something lile that, because that was answered a lot of times (: