You will add 6 steps to the ladder.

The bottom of each step falls on a multiple of 11".

You will measure and make lines at the following measurements: 11" and 12.5", 22" and 23.5", 33" and 34.5", 44" and 45.5", 55" and 56.5", and 66" and 67.5".

Use the circular saw to cut along each line and then make numerous cuts in between each pair of lines as seen in photo 1.

Use a chisel to clean out these notches as seen in photo 2.