What should my friend do with the ATK test on his 5th day after returning to Thailand?

Upon returning to Thailand, your friend is required to perform an ATK test on the 5th day. The test result should be reported to the hotel where the test was conducted, as they will handle the reporting process. Alternatively, it's mentioned that there might be a notification in the Morchana app around Day 7, as some users found references to their testing even during different entry schemes.