What a serpentine belt actually does
A serpentine belt is the poly-v wrap from the crank to the accessories. Ribs sit in grooved pulleys. A spring idler keeps the loop tight.
Start at the crank. The damper is a grooved pulley on the nose of the engine. One ribbed belt sits in those grooves and leaves. That is the serpentine. It is not a set of separate V-belts. One loop. The accessories wait on that wrap.
Follow it. The ribs land in the next grooved pulley — power steering pump, compressor, alternator, water pump if that engine still drives the impeller from this side. The cover has the map. The order is that map, not a guess from the bay. Smooth wheels in the middle are idlers. They take the back of the belt and turn. They do not drive a pump.
The tensioner is the spring in that loop. An arm, a pulley, a coil or a hydraulic strut. It leans on the belt so the wrap does not go slack when a load hits the alternator or the compressor clutch locks. Do not read that wheel as an accessory. It only keeps the ribs in the grooves.
The working face is ribs. A poly-v. Those grooves are what a grooved pulley bites. The back is flat — that is the side an idler or the tensioner rides. Cracks across the ribs, glaze, a chirp on a cold start — the wrap is done. The accessories did not fail. This belt stopped turning them.