Lining and distributing layers to backround

First I would want to create a margin, although there are other ways of doing it.

I've used View > Guides > New Guide Layout

My canvas is 2000 pixels square

With Snap to guides turned on (it should be by defualt) I would move the four layers so they snapped to the top left guide intersection.

Then move the top layer so it snaps to the top right guide intersection

Select all four layers.

Select the move tool and in the Options bar chose  Distribute Horizontal Centres

Note: You'll first need to click on the three dots to make the full alignment options visible.

Nearly there.

Drag the top layer down so it snaps to the bottom right guide intersection.

With all four layers selected, chose Distribute Virtical centres