Thanks for your reply!
I already did that in the project settings. My problem was that even tho each character has been assigned a controller, the controllers were all controlling the same character no.1.
I managed to fix this problem this way:
By saying that the target is “Get controlled pawn”, each player character is being moved by its own controller(gamepad/keyboard).
Another solution I found for this was to simply add the movement controls inside the character blueprint itself with target being “self”. But since I’m using a PlayerController class/blueprint, I had to solve it this way 