Where does the Imam face when he tells the worshippers, "Straighten your rows," and so on: Is it towards the Qiblah or towards the worshippers?

The basic principle is that the Imam should face the worshippers when instructing them to straighten the rows, following the example of the Prophet (peace be upon him), to ensure their compliance. It is narrated from Anas ibn Malik (may Allah be pleased with him) that the Prophet (peace be upon him) turned his face towards them and said: "(Straighten your rows and stand close together, for I see you from behind my back)." And from Nu'man ibn Bashir (may Allah be pleased with him) that the Prophet (peace be upon him) turned his face towards the people and said: "(Straighten your rows)." This is evident from his actions (peace be upon him). The Companions used to ensure the straightening of rows before the Takbir, such as Umar and Uthman (may Allah be pleased with them). There is no harm for the Imam in addressing them through a loudspeaker if the mosque is large or his voice is not loud enough, as long as he is keen on straightening the rows.