You need a basket that is large enough for the dough after it has risen. Line the basket with the towel that is covering the bowl with the dough. Cover the dough's surface with flour and place it on the towel in the basket. Let it rise for about 30 minutes. Place an open flat container with about 1.5 l of water in the oven.
Hot water is quite corrosive.
A stone ware dish, a disposable aluminum baking pan or an old pan that can be dedicated to this purpose is best. Place a cookie sheet on a grid in the oven with sufficient space above the sheet for the size of the dough after rising. The water in the dish should be boiling. After the dough spent about 30 minutes in the basket, let it roll out of the basket onto the hot cookie sheet. This is done by turning the basket slowly upside down next to the edge of the cookie sheet.