The interviewer wants to learn more about your background and experience.
If you don't have any experience, it's okay! Tell the interviewer that you do not have any experience in the industry, and you look forward to making the transition and learning everything there is to know!
If you have experience, start off by giving the interviewer a high-level overview of your experience by sharing where you have worked, your job title, and how long you were employed there. Add a sentence or two about what your job duties were in each role as well. Be sure to mention that you really enjoy this industry, and you look forward to continuing to work in retail industry roles.