Measure the rough opening
Check that the opening is plumb, level, and square
Assemble the door frame if it is not preassembled
Position the frame in the opening
Insert shims behind the hinge side jamb
Secure the hinge side jamb with nails or screws
Hang the door if needed
Check the reveal around the door
Shim the latch side jamb until the gap is even
Secure the latch side jamb with nails or screws
Shim and secure the head jamb
Recheck that the door opens and closes properly
Trim excess shim material
Install casing or trim around the frame
Fill nail holes and finish as needed