Lexmark XC9335
Turn off the printer.
Open door A.
Unlock the used fuser.
Remove the used fuser.
Unpack the new fuser.
Insert the new fuser.
Lock the new fuser.
Close the door.
Turn on the printer.
Change the transfer roller regularly to prevent toner leaks.
Here are the steps to replace the printhead wiper, the small device that keeps the printhead lens clean.