Warehouse hiring event in St. Louis this week - any advice?

I saw a flyer for warehouse hiring on the east side of St. Louis, with day and night shifts. This is my first time dealing with any of this. They said to bring ID and a work history, and some people were hired on the spot. What are the shifts like?

I applied for a similar job last year and the drug screen and background check took about a week. Bring two forms of ID.