The main window of the balcony in the living room faces south, and the auxiliary window faces east or west?

The main window faces south, so it should be better to receive more sunlight. Whether the auxiliary window faces east or west depends on whether your house faces south or north, whether it is in the plain or in the mountains. It doesn't matter if it is in the south, because it is warmer. If you are in the north, you should consider putting it in the west, because the southwest wind is cooler in summer and the northeast wind is colder in winter, so the cold wind can't blow into the house. But if it is a mountainous area, it is different. We should consider the influence of wind direction change on houses, because the wind direction is blocked by mountain wind and should be guided according to geographical location.