In editor blueprints execute only the construction script on creation of the actor, on moving him and on changing a public variable. In that movie you see a plugin with a custom C++ code and interface (you see it to the left). Blueprints can’t create additional interfaces nor buttons (which I would like too >_> ) inside the editor currently. For that you’ll need to use C++.
Though you can use construction script for many things by using public variables. Check out some youtube videos, maybe construction scripts will be what you need.