137:11 On each day of Succos, after musaf, the practice is to bring a sefer Torah to the bimah. We leave the aron open until after saying Hoshanos and returning the Torah. Every one who has an esrog and lulav goes around the bimah where the sefer Torah is while the Hoshanos are being recited. Each day they go around once, except for the seventh day, which is Hoshana Rabbah. On that day, we take out all the sifrei Torah and bring them to the bimah, then we go around seven times. This is done in remembrance of the Temple, where every day they went around the altar once and on Hoshana Rabbah they went around it seven times.
The circuits must go to the right. Since the sefer Torah is on the bimah, and the congregants must turn their faces towards that Torah on the bimah before they begin to go around, then north is to their right, so they go around to the north (This is assuming that the aron is in the east.) If one has an esrog and lulav but he does not go around, he has acted inappropriately. In some places, the practice on Hoshana Rabbah and Simchas Torah is to put a lit candle in the aron after removing the sifrei Torah. This is done because the Torah is compared to light, so when there are no sifrei Torah there we need another light. This is not a good custom, however, and it should be abolished because it is forbidden to use the aron for a secular purpose, even temporarily.
137:12 We do not go around the bimah on Shabbos because they did not do so in the Temple. Therefore, we do not bring up a sefer Torah to the bimah. Instead, we just open the aron until after the Hoshanos have been recited.