To scan an NFC checkpoint that has already been configured, simply hold the device over the NFC token. Once you have scanned the checkpoint, a message will appear below the checkpoint indicating when the last scan was done.
Note: The NFC antenna is located in a specific spot on the device. In some cases, it may be necessary to move the device over the top of the NFC token to scan it.
Due to the limitations of iOS settings for NFC, iOS users MUST hit the 'Scan NFC' option on the phone