Installation of the preassembled medicine cabinet is made easier by first removing the mirror and door from the framework. In our case, this was simply a matter of removing two screws from the door hinges and carefully lifting off the door.
With the door and mirror removed, the medicine cabinet is carefully placed into the precut rough opening (Image 1) left earlier by the carpenters and drywall installers. The assembly is pushed back until it's seated firmly in the opening and flush with the drywall.
A 2' level is used to check and ensure that the cabinet is straight and level (Image 2).