How do I set secret passcode?

To set a passcode, tap on the settings icon at the top left of the people screen. You can get to the people screen from the screen with the photos of all of the people you are tracking by tapping on the people button at the top left of the screen.

From there, tap on the Passcode Lock option and enter your secret code.

Note: if you forget your passcode, you will be locked out of the list.

You can uninstall and re-install the app to get back in, but you would lose any information you entered, so please be sure to use a passcode you will not forget.