Disconnect the spark plug wire
Remove the battery on electric or battery-powered mowers
Tip the mower safely with the air filter and carburetor facing up
Wear heavy gloves
Block the blade with a wood block
Loosen and remove the blade bolt
Remove the old blade
Note the blade orientation
Install the new blade in the same direction
Tighten the blade bolt securely
Reinstall the mower if tipped
Reconnect the spark plug wire or battery
Check that the blade spins freely
Start the mower and test for proper operation