what shoud i write before ("Hello World") to be recognized?And where i should write it ??

Answer 1

System.out.println("Hello world ");

Answer 2

or you can write System.out.print(" Hello World "); you must'nt write the "ln" Little but it can be useful for you later :)

Answer 3

the S must be capitalized

Answer 4

and it should be in your main