Applying online with view to picking up Visa in Person in Brisbane.

I require an express service from the Brisbane CVASC and will fly to Brisbane to pick up. I have not purchased a plane ticket yet as I am waiting to hear from work when I am required to start back. I do have an invitation letter from my friend in Shenzhen and am hoping I can obtain My Visa prior to purchasing ticket as I am not sure of departure date. When applying on line and submitting the application, are you required to print it out, sign it then upload it or do you upload it unsigned and sign when you visit centre in person?