Answer 1

Packages are something like modules, that you can import to use them in your code.
You can create them by adding a new project or simply new subfolders in your existing project to store your classes there.
Make sure that the jvm can find the packages you want to use on the class path.
The easiest way to achieve that is to choose the packages in your ide (usually right click on your project > build path > add project or jar file).
Also you can use tools like Maven, in which you can define a dependency. Then you need a repository where Maven can find the needed source and everything else will be managed by the tool.