In order to keep the lessons as short and concise as can be, they tend not to repeat previous lesson content.
This is definitely up for discussion, but it will always be partly unresolvable. Some campers complain about the amount of hand-holding (code given to help), other campers complain about the lack of hand-holding.
I was going to say the same thing as @Sky020.
This is the second lesson where nesting is required.
The next nesting problems that come up after this is when camper’s are required to do the radio buttons / checkboxes.