You must fill out the signup form for each student for each class.
Thus, to add a sibling or to purchase another class for the same child, you need to add them to your cart one-at-a-time, filling out the form each time. E.g.: Fill out the form for the first child and add them to your cart. Then, go back and fill out the form for the second child and add them to your cart. Now proceed to checkout and purchase all your classes at the same time.
This is so we can collect the name, age, and other details of EACH student and for each time slot separately.
