One fee per person
Every member has their own, with their own amount and their own structured reference. Same family, same account, same rate: they are still two separate fees.
Make one transfer per person
That is the only thing to remember. A transfer of €160 carrying the eldest child's reference cannot be cut in two: it goes onto the eldest's fee, and the youngest's stays unpaid.
Two transfers of €80, each with its own reference, attach themselves. It costs you thirty seconds more; it does not cost your club an evening.
If it has already gone as one payment
Tell your club rather than leaving them to search. They will certainly see a €160 transfer arrive, but nothing tells them it covers two people.
An account paying for two
Your account is remembered as payments come in: that is what lets your later transfers be recognised without asking you anything. But as soon as it pays for two members, the tool stops guessing and hands the question back to your club. That is deliberate: better a volunteer who decides than a fee landing on the wrong person.
Seeing them all in one place
If your children are registered with your email address, your space shows each of them under their own tab: what is paid, what is not, and each one's certificate.
All the help pages
Do you run the club ? The committee’s step-by-step guides are listed on the committee help.