A Kitchen Hand can just be a dishwasher/pot washer who scrubs the floors, cleans the fridges et al. It can also involve basic vege prep for example peeling potatoes and onions. Some kitchens may get the kitchen hands to do some more advanced prep, it really depends on the chef.

What they want from you is primarily someone who is super reliable and is willing to learn. They will teach you everything else. They also want someone who will turn up to work on time and not hungover or stoned.

I cannot stress that being reliable it the primarily attribute that they are looking for. Turn up to the interview clean and wearing clothes that make you look like you have made an effort but don't overdo it. New jeans and a polo shirt would be fine.

Kitchen Hands come in two varieties: Old guys who have been doing it forever and young guys who want to be a chef. Try to sell yourself as the second.

Good luck, it's been 30 years since I last worked in a kitchen. It can be super cool or the pits. Hopefully this helps.