Are you doing a wide hem or a narrow hem? What fabric? Knit? Wool? Poly-cotton blend?
For a narrow hem, follow Aicha's directions.
You may prefer to use a separate wide bias facing or fully line the skirt. Either is ideal on curved hems. With wool, it's possible to steam the hem into shape, but that's a technique more advanced than a full lining or a bias facing. Each of these won't leave the stiff edge a narrow rolled hem will produce.
For a narrow hem, follow Aicha's directions.
You may prefer to use a separate wide bias facing or fully line the skirt. Either is ideal on curved hems. With wool, it's possible to steam the hem into shape, but that's a technique more advanced than a full lining or a bias facing. Each of these won't leave the stiff edge a narrow rolled hem will produce.