In our default boilerplate, the buttons are aligned center. You can always change the position of the button in the block. There are two ways to do that, depending the kind of button you have.
Change the position of square buttons:
Click at the inspect icon at the block and choose your desired alignment:
With this function, you can also align unresponsive images in the block.
Change the position of round buttons:
Click at the button and set the desired position at box align: