Welcome to the Ranch
I recommend if you are a real newbie/noobie, you don't use NetBeans. Use a decent text editor (eg Notepad2, Notepad++, jEdit on Windows®, or gedit or kate on *nix). M$ Notepad is not particularly good, and can introduce confusing errors by adding an extension.
Use the command line. There is something about that in the
Java™ Tutorials; go through that section missing out the OS you don't use and the NetBeans version.
You might have a control character which you can't see preceding the "i" in "import" and the compiler will see that as an error. Both those packages you are looking for are standard sun/Oracle pacakges, which should be inside the file called rt.jar, which you will find inside your Java™ installation folder. So you ought not to have to download anything else at this stage.
More detailed instructions for running LP's little class
Open a command prompt or a terminal (start→all programs→accessories→command is one way to open it on Windows®)mkdir java (or similar name. You can now use that folder for ever.)cd javaEdit a file called HelloYou.java and save it in that folder. Note name of file and name of class should match.javac HelloYou.javajava HelloYouBeware: there is very little scope for spelling errors. Note where you have to miss out the .java extension.