If you do not select a seat, we’ll do our best to seat you together at check-in, at no additional cost. If you choose to purchase a seat, accompanying children's seating is free in the Family Zone.
Rows 18-32 will be initially reserved for Family Zone seating. If these are unavailable, rows 8-14 will become available to families flying with children under the age of 14.

If you want more info on seating regulations you can visit here.