Internal doors --- installation

We are installing internal doors this week.

Steps:
Check plan to find hinge position;
Check floor level.if the floor isn't the same level,cut the jamb bottom(high floor side)
Measure opening and door sizes;
Half left every amount;
Nail three packers first on hinge side;
Nail jamb on packers,make sure jamb is plumb,flash with GIB board;
Adjusting other side and top,gap between door and jamb are small and same.When close door,make sure the door is exactly flash with jamb;
Nail other side and top jambs.