Turn off the water supply valve behind the toilet
Flush the toilet to empty the tank
Hold down the flush lever to drain as much water as possible
Remove the tank lid and set it aside safely
Use a sponge or towel to soak up remaining water in the tank
Disconnect the water supply line from the bottom of the fill valve
Unscrew the locknut securing the fill valve under the tank
Remove the old fill valve from the tank
Insert the new fill valve into the tank opening
Adjust the fill valve height to match the tank
Tighten the locknut underneath the tank
Reconnect the water supply line
Attach the refill tube to the overflow tube
Turn the water supply back on
Check for leaks around the fill valve and supply connection
Adjust the water level if needed using the fill valve adjustment mechanism
Replace the tank lid
Flush the toilet several times to confirm proper operation