In the western hemisphere, the first page of any publication is placed on the right side for printing.
Usually you design the front and back cover in a separate file, that means you will have both pages — front and back — appearing side by side, as long as you use saddle stitching. In case of a book binding with a spine on one single sheet you will have the back cover on the left side, the narrow spine in the middle and the front cover on the right side.
If it helps (though not for printing), you can specify the left page being the first page, as long as you don't intend to have it printed: