How do I set a passcode to keep the list secret?

To set a passcode, tap on the settings icon at the top left of the list of people or stored to launch the settings view.

From there, click 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.