Very casual, if you get past the online assessment the interview is a piece of cake! Usually just ask you about yourself and what you're interested in. There is a section regarding different experiences you've had e.g. times you had to handle conflict, had to think outside the box and helped a customer etc.

Standard retail interview, make sure you have a question prepared to ask the interviewer. They go through your cv on the day so make sure you have the correct dates etc.