If you apply online you should receive an email with a few questions about yourself. Your hobbies, reasons for applying etc... Just sound outgoing, fun-loving, and also make it clear that you are a hard and FAST worker and you'll get an interview set up! They have a high turnover rate, so they interview 4-5 people in one day about every other week. Look sharp, and bring a resume, and don't be nervous. This interview is very relaxed and easy to get through, it may be 2 minutes, or it may be 20 depending on the day. Speak loudly and don't ask too many questions. Generally this is the last interview, they'll either ask you to come in for a training day, or they'll say thank you, this job is not for you.