Warehouse job needs 3 interviews. Need advice on nailing the third

So I recently interviewed at a warehouse as an order picker. I have worked this kind of job before a few years ago, and back then it was very straight forward. I interviewed, they liked me, and then asked when I could start the next day. For some reason this job (which only pays $15 an hour) needs 3 interview rounds. I have never had to deal with interview rounds at any job I have had; only a basic phone interview which lead to an in person interview.

I had my in-person interview, and did fantastic, and then was asked to move on to the third interview round. My second interview just consisted of a lot of warehouse specific questions, as well as plenty of behavioral questions to figure out my communication, problem solving skills, and conflict management skills. At the end, I was told that they were going to see more candidates and that I would know soon whether or not I was accepted to go to the next interview round. Luckily, I was accepted to move on to the third round, and I need advice as to how I should prepare. This is something I have not dealt with before, and I really do not know what could be discussed further as to gauge whether I can perform this pretty basic job that I have already done before.