Run test transactions. Run stuff through the production gateway. Try to test the realtime listener and audit processor.
Which of their products are we using now? They've pitched a few for us to investigate, but let's focus on the shortest path to success:
- Client Side Encryption: https://docs.adyen.com/display/TD/Client+Side+Encryption
- Hosted Payment Pages: (https://docs.adyen.com/display/TD/HPP+Manual) and create 1 or more Skins (https://docs.adyen.com/display/TD/Skin+Manual)