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  1. Click on Code
  2. You can choose Blocks or Blocks+Text or Text*. For beginners, it is recommended to use Blocks + Text.
    1. This allows you to see the C++ code generated corresponding to your blocks.
    2. You can copy this code later into Arduino IDE to program the real Arduino, rather than having to write it from scratch.
    3. You can also download the code as an Arduino-compatible .ino file. 
  3. You can code by selecting the blocks and connecting them appropriately.
  4. You can start the simulation by clicking Start Simulation.

*Note : You can go between Blocks and Blocks+Text anytime. You can go from Blocks / Blocks+Text to Text, but you can't go back from Text to either of the other two (converting blocks to text is easy, converting text to blocks is computationally non-trivial).

You have to click Stop Simulation to stop the simulation before you can modify your program and/or hardware connections.

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