Instructions
Load "LittleBigPlanet" and select "MyMoon" from the main menu. Select a stage to load, either an existing level or create a new one.
Open your "Popit" by pressing "Square" and you will see the "Tool Bag" grayed out. At the top of the menu you should see a "?" icon. Press it to begin completing the creation mode tutorials.
Complete all the creation mode tutorials until you unlock the "Tool Bag." Several "Tool Bag" subcategories, such as "Dangerous Tools," are unlocked by completing more tutorials. This is the only way to unlock most of the materials and gadgets to use in creation mode.