I am a Beginner in java and I need help desparately. I have a project that I have been assigned and it is to biuld a functionality to process a credit card batch payment. I have done most of the work, now it's time to do the implementation and I don't know where to begin. I already have my use cases and the sequence diagram, but I can't seem to get started on biulding the classes, etc. Could you please show me how to get started?

start by building the gui .... and then you'll be able to extract your imagination of the methods that must be used.