How do I replace the belt tensioner

My S10 needs a new serpentine belt and belt tensioner. It seems like no problem but I was wondering about the tensioner. I have never taken one apart. It looks like there is one bolt in the center - if I take that out there I want to make sure there will not be any like spring flying out and I can't get it back together without a "special belt tensioner spring retractor tool" or some such device. Anyone replace one of these?, mine is squealing pretty good.

Remove the sserpentine first, then remove the bolt. The tensioner will come off. When installing it, you will see that it can only go on one way. After you have that on, then install the serpentine.