Here are the steps to follow in order to read your cards. Your goal is to find as many keys as possible. The keys unlock sections of your card for the Flipper to read them - you must have a card. Once you read enough sections, you can use an emulated or cloned card at the original card reader to unlock it (sometimes even without finding all of the keys!).
Important
Major update coming in first update following OFW 1.0.0 (ETA: mid to late September) which overhauls and simplifies this process:
Steps:
