Do not send payment to Pearson-Vue until you know that your credentials have been accepted by the BON; they will notify you when they have been. They also need to notify Pearson-Vue as well, Pearson-Vue does not have the authority to just release the ATT when they receive the payment.
This is applicable to foreign nurses that wish to get licensed in the US, it is different if you went to school in the US.
Fl BON does not issue the ATT, that comes from Pearson-Vue. And once they have received the approval from the BON and you have paid the fee, they will release the ATT. And then you have a 90 day window to test in.
Best of luck on your exam.