From the main menu head into the Pod controller and scroll right to 'My Moon - My Levels' and select a space to create/edit.Note: Creating a world with a pre-set template will help to increase the thermometer before you begin.
Once in the world add items from your Popit to build up the thermometer to over 30% full (Larger the item the better)
Once done press
and save the level to earn this (Note if more than one person is in the game you can also get
The Team Creator trophy in LittleBigPlanet worth 28 pointsBuild and save a level with more than one player with the thermometer more than 30% full