I believe you are correct, that the blue barrels have to be hung, just like a pack.

As far as hanging, I've always hung my food pack. I've assembled a rope and pulley system that makes it pretty simple. I'm not good at diagrams here. Three pulleys gives me a 2:1 advantage. I store in an old canvas coin bag and use that with a rock to toss line over limb. There are many descriptions and you tubes. I think the one common thing is preventing snags in the tree.

Many say they hate hanging but honestly, I have always looked forward to it, a kind of sport, from hunting for the right tree to the toss to remembering to get everything - good, garbage, toiletries - in before flying the bag.

Probably should disclose I'm a professional theatre rigger, so it all seems pretty simple and natural to me.