Super Mario Maker's suite of level designing tools will slowly unlock over the course of nine days.
Every day that you play the game for more than five minutes will queue up a delivery of extra items and level blocks for use the day after.
This means that you will start construction on your first level with only a simple range of blocks available, such as the good old question mark item block, and only a couple of enemies: Goombas and Koopa Troopas.
Later days will unlock items such as the flying Koopa Clown Car and enemies such as Bowser himself.
You will eventually be able to place musical note blocks, add visual and sound effects, and even record voice clips yourself. (Presumably these will not be available when you are uploading or downloading courses over the internet.)
Nintendo took a similar approach to unlocking content in recent Wii U shooter Splatoon, although over a much longer time-frame. See which items you get on what day via the video below: