You're not adding your button or your JPanel to anything, and so no JFrame is magically going to display them.
You should add your JButton to your JPanel via its add(...)
method, and then add the JPanel to the JFrame via its add(...)
method, and do so before setting the JFrame visible.
Most importantly, you should read the Swing tutorials, since I speak from experience when saying you'll get no-where just guessing at this stuff. This is all well explained there.
As an aside, avoid setting the sizes of any components and instead read the tutorial section on use of the layout managers as it will allow you to simplify and empower your code greatly.