You apply on the website, where you provide your basic information as well as take a (very long) personality test. One of those where a statement is provided and you have to choose whether you agree with it or not. (i.e. "Stealing is wrong", "agree/disagree/not sure".)
After that, you had to go into the store to use their PC to do a skills test. This stayed the same throughout my time there, though it may be different now. The skills test differed based on which job interests you expressed during the initial application - I had indicated service clerk, photo, and pharmacy technician, so I got a pretty lengthy test consisting of mental math, reading photo labels, and reading medication labels. I think the testing process is a bit more robust now with videos and whatnot, mine just had still images.
After completing the application and skills test, I received a phone call a few days later asking for an interview. It was my first interview for my first job, so I was a bit nervous. I was given a time to show up , and then I walked into the store, where I asked the clerk on duty to summon the manager. The manager then led me into the office, where the interview took place. It was just me and the store manager, though other managers went in and out of the office while my interview was being conducted.
It was also a long time ago, so most of the questions escape me. I do remember a few:
"Tell me about yourself."
"Do you have any retail experience?"
"How would you deal with an irate customer?"
When the interview concluded, the manager told me that I would have to take a drug test, and I would receive a phone call the same day with a decision (conditional on passing the drug test). I did, and was offered the job.
Came in on my start day and did the usual paperwork. It will probably be explained in the interview, but you should wear a blue (exact shade not important) shirt and black pants., as well as a tie if you identify as male. They used to have company uniforms, but not anymore.