How do i add bonus power ups

I am making a breakout style game on unreal 4 and have no idea what I am doing. I manged to come up with a basic breakout style game following a tutorial. I now want to add a times 2 bonus to a random brick, so the brick changes every time the level or the game is restarted. I can make the brick, but when the brick breaks I want there to be a x2 bonus on the score counter, which iv implemented and works. I want a fire bullets bonus which is also in the game ready and works, just I don’t want it to be on all the time. how would I create the blue prints for this can I have image of the blueprint graph please Thank You