Spread out the full length of the tartan.

Leaving an arm's length unpleated, begin making your pleats by hand & continue to an arm's length from the other end.

Pleats in the middle
Unpleated on each end

Fold the unpleated sides in a bit to slide your belt under.

Lay down on top. Fold the right unpleated end over the front of the body, then the left. Fasten your belt & stand up.

Now comes the fun & creative part. Half of the tartan will be hanging down over the belt. Just start playing with the tartan to fashion a variety of looks on the upper body.