Use the Alignment tools to position the matrix grid on the canvas. The default position is the upper left corner of the canvas, but you can align the grid in a different location if required.
Open the Alignment drop-down from the Component ribbon:
From the alignment drop-down, select one of nine presets:
Here, the grid is aligned to the top left corner of the canvas:
Here, the same grid is aligned to the centre of the canvas:
And here, the grid is aligned to the bottom right: