Q: how do you eat an elephant?
A: one bite at a time!
It really depends what you want to do. Are you interested in games, database applications, accounting packages or something else? You have to set a priority and go in that direction. If you are not dying to do something, perhaps practice some Swing. Start with cheap materials like the Java trails at Oracle or the API documentation.
The one thing I don't recommend is saying that you don't know that much. Try to use what you have as best you can.