Parts Avenue

Okay, I was used to the old fan belts. Loosen something on a swing bracket, change the belt, wedge a prybar under the component and tension the belt, then tighten the bolt.

I'm looking under the hood of my 1999 GMC Suburban and I see NOTHING that I can swing out to change the serpentine belt. I do see one wheel that looks like it might be there for tension (because it's just a wheel and not an engine component), but I don't know if I need a special tool to tighten the belt once I change it. (yes I see the diagram for the path, so I don't need that help).

So if I loosen that bolt and change the belt, how do I get the belt tight again?

Also, am I going to affect the timing of my engine by changing this belt?