Your first payment (which is the upfront payment) will be due upon confirmation from the merchant. Your subsequent monthly payments start in the following month, or the one after that, depending on the day of the month of your first payment.

Each monthly payment will be due on the same day of the month throughout the loan period, based on the date you selected (8th, 18th or 28th). 

For example, if you obtain a loan on January 15th with three monthly payments of 28th, your first, second, and third payments will be due February 28th, March 28th, and April 28th respectively.

Don't forget, you can see all your upcoming payments, and the date they are due, on your personal account page.