You need to fill in the DS-156 form at http://www.usembassy.org.uk/cons_new/visa/niv/electronic.html - fill in the form online, press continue and then print it out - take the print out to the interview! If you are male aged 16-45 you need to fill in form DS-157 at http://www.usembassy.org.uk/cons_new/visa/niv/add_males.html - fill it out, print it and take it with you. There are some answers for some of the questions on the "Applying for your Q1 Visa" help sheet that Yummy Jobs will have sent out with the petition info - ask them for it if it hasn't arrived! When is your appointment?