I started with one phone screen with HR followed by another phone screen with the engineering manager. The HR screening was simple, about what you'd expect from any HR interview. The engineering phone screen was also relatively simple. The only unusual part was a math question. This should be something like: a driver can drive x mph to his location and x mph from it back to the base. He can deliver x packages per hour upon arriving to his location for the day, and he works x hours with x minutes for a lunch break. How many packages can he be expected to handle that day? Just know how to solve that type of problem before you start the interview.
As others said, it's a BAR (behavior-action-result) format interview if you make it to a site visit. There were two employees interviewing me for this section. I wasn't instructed to use that format when I interviewed, but I saw the advice on Glassdoor and they seemed to appreciate that I used it anyway. There were 8 behavioral question, and then the ninth and final question was a "sell yourself" question: why should we hire you instead of someone else?
If they recruited you with a low level of experience, they're looking for you to justify why you'd be a good employee regardless of your lack of experience. I was surprised by the question due to inadequate preparation, but after answering it seemed to me that they were actually looking for me to talk about other skills/traits that didn't come up in the interview with justification of why I have those skills (e.g. college courses, outside volunteer work, a serious hobby). Don't just focus on one aspect. They really want you to go all out for that question.
The behavioral questions are all simple. I practiced by googling a list of common behavioral interview questions and managed to practice 7 of the 8 questions before the interview. Writing responses beforehand was helpful, and I'd strongly recommend it. Obviously you can't bring them in, but they made me think about what to cover before I reached the interview room. If you're a recent graduate, they don't mind if you use school or volunteer experiences instead of work experiences for some of the questions.
During the process, you'll also interview with the engineering manager. You've talked with him by phone earlier. Now he'll just get to know you a little more and ask a different type of math question. If you had the number of packages delivered question over the phone, now you'll answer a frequency question. Mine was: you have one employee to do 3 sequential tasks. He can do task A at x items/hour, task B at y items/hour, and task C at z items/hour. If he's the only employee doing all three tasks, how many items can he process per hour? Again, relatively simple, but you'll feel more confident if you practice this type of problem before you go to the site interview.
Overall, all of the employees I talked with at the site interview jumped on the chance to make things personal, so don't be afraid to mention stuff about your own life. I met current employees who were alumni from my college because I arrived a little early, and I'd definitely recommend checking out LinkedIn for alumni from your own college if you want to do the same to maybe stand out more.
I was told to set aside 3 hours for the site interview, but it ended up taking 2 hours. There is a guard that stays behind a desk who needs to buzz you in from the visitor's entrance. After that, you'll wait for your HR interviewer to escort you to the right room. The company compensates for miles and wear and tear if you have to drive to the interview, and it took a couple weeks for the check to show up. It took a couple days after applying to schedule an interview, then about a week to do the phone screen and another two weeks or so for the site interview. After the site interview, I heard back in one month.