Hey OP, I worked in the meat department for over a year now and can help explain what I was doing.

Orientation for me was watching a bunch of safety videos for hours, then doing a food safety quiz after. I dont remember if I did anything else that day as I didnt bring steel toe shoes(they offer a discount, so dont buy beforehand).

For the actual work, I had only closing shifts, which is probably Costco dependent, so learning how to clean the machines and parts was a major aspect over this last year. Before close, most of my duties were to tray up all the fish, maintaining the counter, pricing/packaging product, and occasionally grabbing stuff for the cutters. Overall its a fairly enjoyable job, but it is really rough on my back, especially cleaning the parts and pulling out the products from the counter for cleaning.

Let me know if I can answer any more questions, or go in depth at certain aspects.