They first sent you an email to set up the first phone call. The first round is pre-screening where they ask questions about your transportation, work authorization, work schedule. On the 2nd phone call, they asked behavioral questions

First interview if they like you they set you up for a second interview sometimes same day sometimes a different day depending on schedule then at second interview if they like you they have you sign up for background check after check clears 1-2weeks they call and set up orientation