So when making a ladder diagram for the number 66, there are multiple possible options for the first number, 2 is given, which leaves 33, which then becomes 11 and 3. If you had started with 11, you would next have 6 which would immediately become 2 and 3. The ladder will always have the same number of offshoots (2, 3 and 11 in this one) so there is no one right answer for the first step of the ladder.
Hope it helps :) :) :)