Unless you booked through one of the on-line travel agencies that do not participate, you should receive an offer to Royal Up after final payment is made.
You should receive an offer to bid on higher room types, including suites.
You can make one bid per type of room and can go in and change your bid until it is either not accepted, accepted, or until it is closed.
When I logged in just now to capture the below screenshot I was taken to a screen where an existing bid I have in place was shown and given the opportunity to modify my bid or to cancel it. We sail Feb 18th.
Here is a screenshot of a partial Royal Up page for my sailing.