Measure where on the door you will be installing the handle. 100cm (41 inches) from the floor is most common used. After deciding the height of your door handle, measure where the spindle will be installed using your door handle and mark it on both sides of the door. Then using the same measurement, at the side of the door mark the centre with a pencil. If possible, place a door wedge under the door to stop the door from moving while you are working.
Use a 2mm drill bit and drill pilot holes in the door on both sides and the centre where you previously marked.
Insert a larger drill bit and use this to drill all the pilot holes on the front, back and side of the door.
Attach a 25mm spade bit and drill into the centre hold of the front and the back of the door for the spindle to be inserted.
Using the same spade bit, drill a hole in the side of the door that lines up with the holes on the front and back. Be careful to drill the hole square from the door so that the hole is drilled at the correct angle.
Insert the latch into the hole you previously drilled at the side of the door and with a 2mm drill bit, drill pilot holes where the screws will fit the latch to the door. Use a pencil to draw around the faceplate and chisel out a hole for the latch. Then secure the latch by screwing in the top and bottom of the latch.
If you are installing a striker plate, close the door and mark on the door frame where the barrel is. Mark where the striker plate opposite to the centre of the latch on the door frame and then drill a pilot hole in the centre. Attack the 25mm spade bit and drill into the pilot hole.
Hold the striker plate up to the hole you drilled and use it to draw an outline. Then using a sharp chisel and hammer, chisel out a hole for the striker plate. Insert the striker plate into the hole and secure by drilling 2mm holes and then secure it to the frame with the top and bottom screws.
Insert the spindle through the centre hole going through the front and back of the door and attach the door handles into the spindle holes. Make sure that they align horizontally and vertically. Drill pivot holes and then screw the handle plate to the door to secure in place. Test the lever to ensure the spindle is properly attached.