How to work with instances?

HI, I have a problem where all my instances of an actor blueprint behaves the same. And by same i mean if in blueprint a force is being applied on a condition being true then the force is applied on all the instances rather than a single one . For example in my game when you come closer to a box a force is suppose to push it further from you, and there are multiple instances of the same box on which the force is applied but out of range. now in game when playing when the player reaches near one of the instances and force is suppose to be applied its being applied to every instance thats there in the game rather than just on the instance that is in the range. or another example being the health if I am shooting an enemy instance then all the instances are taking damage. Basically all the instances behaviour is same . I have tried creating child of the blueprint and then copying the child all around the world but then its not working. I have tried blueprint interface but I dont understand blueprint interface fully so i dont know if I am on the right path or not. So I want to ask what is the procedure to work if you have multiple instances of an actor bp in the world spread around so that they dont behave as clones of each other?