Instructions
Highlight the badge of the level you want to lock from the Moon menu. Press "Square."
Edit the name, description and icon to your liking. Click "Publish."
Highlight "Locked" and press "X" to lock the level.
Highlight the red button and press "X" to publish the level. Now a key to the locked level will appear in your Popit menu.
Highlight the badge of the level in which you'd like to hide the key in. Press "X" to edit it.
Walk to the point in the level where you'd like to hide the key. You can add it in plain sight (near the end of your level, for example) or hide it.
Press "Square" to open the Popit menu. Highlight the goodie bag and press "X" to open it.
Highlight the level key and press "X." Use the left analog stick to determine the key's placement, then press "Circle" to go out of your Popit menu and drop the key. Now when community users obtain this key, it will open your locked level.