Draw a diagram of the mower belt and how it routes around the pulleys on the mower deck. If you have the owner's manual, you can refer to it for proper belt routing and forgo drawing the diagram on your own.
Cut the old belt off of the mower with a sharp utility knife.
Find the electronic clutch locator retainer at the rear of the mower and loosen both bolts that hold the retainer in place with a wrench. The retainer looks like a square metal plate with one corner cut out at a 45-degree angle. It is out in the open for you to easily locate. Do not remove the bolts.
Locate the belt guards next to the clutch pulley mounted to the main shaft on the bottom of the engine and loosen the bolts that hold the guards in place with the wrench. Rotate the guards out of your way.
Remove the bolts that hold the ball joint that secures the front of the mower deck to the underside of the mower with the wrench then pull the ball joint free of the mower.
Place the PIX belt 754-0371 onto the pulleys on the mower deck. Again, use the diagram you drew or the one listed in the owner's manual. Place the belt over the clutch pulley mounted under the engine.
Slide the guards in place and tighten them with the wrench.
Place the ball joint back onto the mower and secure it with the wrench.
Tighten the bolts for the electronic clutch locator retainer with the wrench.