On your first two days you'll more than likely be doing computer training. The training takes about 16 hours to complete and is VERY BORING. You'll want to wear something comfortable no blue jeans though. You'll be given a shirt, temp name tag, and some OSHA paperwork if it wasn't given to you when you did the hiring process there might be some paperwork signing as well.
Welcome to Kroger. It's sink or swim once you reach the floor. Be prepared! Ask for a tour of the store and if they are able to tell you if there is anything important you'll need to know while getting started. Always ask for help if you get stuck!
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Would you like fries with th... I mean, your milk in a bag?
The computer room at my store is always cold, so bring a light jacket or something so you don't freeze to death before you even get started. You'll get to freeze in the winter.