YES, you do exactly that. Based on my own personal experience, you cannot do online check-in if a coupon code is used. Just go to the kiosk, scan your reservation code, and verify all your info, then go over to the garage and pick your car class according to your reservation. As long as no changes have been been made, you should be fine. Show your license and paperwork to the exit agent and you are on your way!!! Have a FANTASTIC vacation!!!!
Ok, I have experience with this too. Make sure you scan your VISA card at the kiosk and not your MASTERCARD if you have one. One year my hubby did that and it said his card was "INVALID".

I told him I reserved with the VISA card and VISA discount so once he scanned that, all was well.

When we got to the hotel he quickly flipped out his MASTERCARD to make sure it was OK.

He never had a card declined so when he saw INVALID he quickly thought the worst!!! The look on his face was priceless!!! So remember to swipe the right card and you will be fine.