[whynotthinkwhynot]

I'll fix that ---> serpentine.

I recommend Gates parts for both the tensioner and the belt. You'll want to draw out the pulleys and the belt so that you can put it back on correctly if there is not a schematic for the belt located under the hood.

To release tension from the tensioner, use a wrench or a socket if you can fit one on the bolt in the center of the tensioner pulley, and rotate the tensioner. I usually flip the belt off the crank pulley while holding tension off the tensioner.