RE: How do you replace the serpentine belt?
There may be a routing diagram on a label on the rad support for your belt, if not, take a picture or make a drawing.
Use a ratchet or a flex bar to remove the tension from the belt.
Slip the belt off the alt pulley, then allow the tensioner to go slack.
Completely remove the belt.
Remove the tensioner mounting bolt and tensioner.
Install the new tensioner.Tighten the tensioner bolt to 37 ft lbs.
Start the belt around the crank pulley and work it in to place, (alt last)
Use your ratchet or flex bar again in the tensioner to move it far enough to install the belt.
remove the tool, check that the belt is properly in all the grooves on all the pulleys and then start the engine.