First window is letting you know exactly which teeth on the trigger wheel it knows will be TDC for the next cylinder based on the TDC after the trigger value
so you have First trigger tooth as 2 , that means for your V8 will have another event in 9 teeth
36*2 = 72
72/8 = 9
so 2+9 = 11 , 11+9 = 20 and 20 +9 = 29
It then adjusts the trigger table for you so that it uses a 0 as the starting point. That means the trigger table has the "trigger teeth sequence" values and deducts 2 from it as you selected 2 as the first trigger tooth.
So 2 becomes 0 and the table ends, it starts at the other end at 11 which is now 9, then 20 which is now 18 and 29 which is now 27 and then repeats.
