Serpentine belt installation

I have a the car listed above that I need to put the belt back on the pulleys. I’m having a problem getting to the tensioner. I have the serpentine belt wrench set from AutoZone, but I just cannot get the darn thing on the tensioner to loosen the tension. Next issue: once I do finally get to it. I’m hoping from underneath where there is a gap in the underside guard of some kind , apparently I will need to be able to keep a hand on the wrench while re-setting the belt?? Please help soon if possible. I’m headed back over to the car I awhile to try again. Thank you for any help on the matter sir.