Arduino program selector

The program is now saying it is downloaded, but i cant apply it. And by that, I mean that when I set up the set for the programming, and press the trigger, it will not work. I have already changed my programming, but I'm new to this so is there a way to make the Arduino pick a specific code. Sorry for the newbie questions, but I would really appreciate an answer.

Try uploading the blink example that comes with the IDE.
Does the L led on the board flash?

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