Cavermark

I have a idle speed problem p38 4.6 gems. It's idling high. Run on diagnostics today and saying throttle position sensor. I have removed today ready for new one coming tomorrow. Is there a right or wrong way to put it on? Also should the metal shaft the tps goes on turn freely? I tried to turn it with my fingers and it seems solid. Also will I have to set it up again with diagnostics? Many thanks Mark