1. Remove the old hatch lid and frame.
2. Clear the area and measure out the joists to cut.
3. Cut and remove central joist. Brace joist.
4. Add secondary bracing measure and remove plaster board.
5. Measure, cut and add cross brace.
6. Now the hatch has been enlarged, disassemble the ladder and install the frame.
7. After disassembling the ladder keep the springs, hooks, rod and feet to one side. Fix the ladder framing in place.
8. Install the ladder. Fix the back hinges in place first, then the side arms.
9. Pull ladder up and re-attach springs.
10. Measure the distance between the hinge and the floor.
11. Mark the length against bottom piece of ladder.
12. Cut out step if necessary.
13. Cut off excess ladder.
14. Break away and add feet.
15. Make sure that the feet fit against the ground firmly.
16. Test that the ladder folds away, opens and closes correctly and you're done.