Once you have Submitted your classes, you should then view your invoice. and you scroll down and make your payment. (Be aware, there is a charge for installment payments.)  When you Push the Payment button, you will be sent to Paypal, where you can use Paypal or a credit card. If you have not allowed SU access previously, the pop up to Paypal will be blocked. Look at the upper right hand corner of your browser (if Chrome) and allow the popup access.You have to click on that link and follow the instructions to allow popups  Otherwise, you will not get into Paypal.This will result in the Pending note you received.  You will always receive a email from Paypal letting you know what you have just purchased. If you do not get an email, you have not purchased your classes and you will see the "Pending" note in your invoice.