Simply enter the age of each adult traveller in to the adult boxes, and the dependant children (years 0-20) in the children boxes, one after the other. Only use as many boxes as you have travellers.
For Example
A single traveller of age 29 would enter their age as follows:

A family of five (2 Adults and 3 Children) whose ages are
42, 40, 10, 5, 2 would enter their ages as follows:
