I actually got hired from one of those events! Not sure if you will be in a group interview but mine was groups, and I just made sure to answer the questions first and try my best to be confident.
The questions were basic like, why do you wanna work for starbucks, tell us about a time you RECEIVED great customer service (that question really confused me LMAO i had to make stuff up) and i can’t really remember anything else they asked. basic normal interview questions mostly. Be confident and try ur best! you’ll do great, and maybe bring a resume with you.