diodiola

Hi, I am about to move in to my new HDB and I would like to invite Guan Yin. But I heard some say that need to set a 天公炉 also. I would like to verify the saying. And how the 天公炉 should be place as now new HDB corridor all facing other units there is no place where there is actually a place facing directly to the sky. Can i just put a 香炉 or do i need to get those kind with a roof. Please advise. Thank You.