How do you replace drive belt for 2003 Nissan Xterra?

To replace the drive belt on a 2003 Nissan Xterra, first ensure the engine is off and cool. Loosen the tensioner pulley using a wrench to relieve tension on the belt, then remove the old belt from the pulleys. Route the new belt according to the belt diagram usually found on a sticker in the engine bay, and then re-tighten the tensioner to secure the new belt in place. Finally, start the engine to check for proper alignment and function.