Measure the rough opening
Check the floor for level and the walls for plumb
Assemble the door frame if needed
Place the door unit into the opening
Insert shims at the hinge side
Check the hinge side for plumb
Fasten the hinge-side jamb to the framing
Hang the door on the hinges
Check the reveal around the door
Shim the latch side until the reveal is even
Fasten the latch-side jamb to the framing
Shim the head jamb as needed
Test the door swing and latch
Adjust shims or hinges if needed
Trim shim ends flush
Install casing and trim
Fill gaps and nail holes
Install hardware and strike plate
Test the door again