How recognize if a arduino board is working or not ?

Hi,
I'm working with a Arduino Uno board and i read in the book " Le grand livre d'Arduino" of Erik Bartmann that a arduino card when you plug in the board the led on it is on for one second. But i try with two different board for one the led is still on if it's plug. For the second the led is on but it's alternative. Is its work or not ?

Is its work or not ?

Can you upload a sketch to it? If not, then no.

Does the sketch do what you expect, like blink the onboard LED? If not, no.

As @PaulS has said uploading the Blink program is the simplest test.

If you make a copy of the Blink program and make a big change to the blink rate and then upload the revised program it should be obvious that it has worked if it is now blinking at the new rate.

...R