Trying to book Ipswich tickets

Hey all, i'm trying to book tickets for my little one whos 6 months old, but the website fir ticketing seens confusing and i cant book an under 14's ticket in the family zone.

It says u3's are allowed, but then says no u2's elsewhere and when booking, i cant even book in the family zone. So frustrating when were travelling from Australia!

Cheers