If it's anything like the M62 which is the previous gen engine it should be on the passenger side and only take about 15 minutes to replace but you'll have to remove the intake box.
EDIT: it's actually in an easier location, the video below should clarify.
https://www.youtube.com/watch?v=CSaLAPhoHhE
Read some of the comments in the video... someone mentioned the rattling noise was caused by the water pump. You should still change the tensioner though.