If you've only got 10m2 then cut the wheat with the
straw attached, make it into hand sized bundles and smack the grain end around inside a
bucket, hit it off the sides of the bucket until all the grains fall off, then take the bucket to a windy area and pour the contents from one bucket to another one, vary the distance between them until you get the grain in the bottom bucket and most of the chaff blown away.