I know a fair amount of java but I’m not sure how to get started on actually creating code for the robot.
The authority: screensteps live and the WPIlib javadocs.
If your new to coding the robot I would suggest a good frame work to build off of. The Command Based robot is a great way to compartmentalize the different subsystems of the robot so you can focus on parts of the machine. RobotBuilder will get you the frame work for a Command Based Robot you can build off of.
Not sure what you mean by “get started”. FRC has a fairly good step by step that “should” get a basic bot moving using Command or Iteritive Robot Sample code.
Good Luck