A drive belt runs different engine accessories on a vehicle. The drive belt is called a serpentine belt when it winds around various pulleys under the hood. Later Toyota Corolla models have a single drive belt with an auto adjusting tensioner system where the tensioner pulley keeps the belt adjusted.
Look at the belt routing (the way the belt runs around all of the pulleys). If you do not find a belt routing diagram under the hood, you'll want to make your own sketch.
Find the belt tensioner pulley, usually located just above the crankshaft.
Insert your 19mm ratchet or breaker bar tool into the tensioner bolt head and pull toward the front of the vehicle to release tension on the belt.
Slip the old belt off of the pulleys.
Reference your belt routing diagram to get the new belt seated on all pulleys. Make sure any grooves on the belt rest against grooved pulleys, and that smooth belt surfaces contact smooth pulleys.
Slowly release the tensioner and check for correct belt tension.
Run the engine and observe for flapping or noise, signs of incorrect installation.
For optimal maintenance, check the drive belt every 6,000 miles or 6 months for possible replacement due to normal wear. Inspect the belt for excessive cracking or rotting.
Older models often have two drive belts that may not be adjusted automatically. Check your model year for detailed information.