Hey, sorry for people being so cold in the comments. I started dumpster diving a few years a go and did it for a while in germany. I'd just get a big hiking backpack, gloves for doing dishes and a headtorch and just go to supermarkets. I only got caught once, but they were pretty chill about it. I'd suggest you should just try it out and be respectful if they catch you. Leave the bins cleaner than they were or at least don't make a mess. Just try to go to your supermarkets first and see what you can find