The term fee is paid by bank transfer to the account in your confirmation email, or in cash at the office on a class afternoon. A receipt with your enrolment reference on it is emailed once the money arrives.
A second child from the same family pays less and the office applies that when it confirms, so there is nothing to claim and nobody has to ask in front of anybody.
If the fee is not possible this term, write to the office before the term starts. That conversation is had privately with the principal, it is not recorded on the enrolment, and it does not come up again when the child enrols the following term. Places have been kept on that basis every term the centre has run and it is not treated as remarkable.