How do you install the show head pipe so that the 45 degree down angle is at six oclock

Shower Arm has one end straight and the other bent under 45 degrees. You insert the longer piece into the wall and screw it in. You stop when you feel the pipe is firmly attached inside the wall and when the shorter side is at 6 o'clock.

If it's still loose wrap more turns of Teflon Tape around the threads and try again. Good luck, Tom