Place the mower on its side so the air cleaner faces upward.
Remove the two bolts that secure the drive belt cover on the top front of the mower deck with a socket and ratchet. The bolts secure from the underside of the mower deck. Squeeze in on the sides of the cover and pull the cover off the deck.
Remove the bolt from the center of the mower blade with a socket and ratchet, then pull the blade off the mower.
Remove one bolt on the belt guard, then loosen the second bolt with your ratchet. Swing the belt guard out of the way.
Pull the belt off the pulley mounted under the mower, then pull the belt through the access hole in the mower deck toward the front of the mower.
Remove the belt from the pulley on the transmission and discard it.
Place the new belt onto the transmission pulley, then place it through the hole in the deck.
Place the belt onto the pulley under the mower deck.
Swing the belt guard into place, tighten the first bolt, then reinstall the second bolt.
Place the mower blade back onto the mower and secure it with the bolt and socket.
Place the cover onto the mower deck and secure it to the deck with both bolts. Use your socket and ratchet.