After submitting my CV online, they just called to tell me I have an interview with them. Also, it alright if you don't have any experiences, because i didn't beside my work experience the school made us do.
The interview was like a quiz, sort of, the interviewer had a sheet of paper with questions and i'd just answer them and he'd write what I'll say, The questions would definitely link to the job you were applying for. For example, applying for the role of Sales Assistant: what would be the top priority from the 3 - customer service, picking up and another one but I forgot. Also, it'll be beneficial if you do a background check on Primark - history, name, what they sell, facts, etc.
Tip, bring essential documents (passports, national insurance etc.), even if you think they're unnecessary.