Can't get these damn buttons to be in the center

To keep a long story short, i'm doing my Uni work and I can't for the life of me figure out how to get my buttons on my web page to be central. I've made them into a btn-group-vertical (basically to make 2 buttons one on top of another vertically). But it clings to the left hand of the screen. I've tried CSS, making a class and using a div to move the grouped buttons. If there's an easier way to do this, please tell me. It's driving me up the wall