The specs indicate the main bed is a queen size, (doesn.t specify reg queen 60x80 or short queen 60x75). I use the same sheets as at home, bought from Sears, Walmart or wherever. In the RV, short queen, I just tuck the last 5 inches fitted sheet, under the foot end, never had a problem. I know others will buy clips?? to hold the corners.
On my overhead bunk, 2 piece mattress, I use twin size fitted sheets, tucking the excess in.
For your bunks, doesn't specify width, you may need full size or twin size sheets and tuck the excess under, foot or sides.
Ken