I grabbed a random youtube. I could not find one that showed underside better that was not done by a company (advertisement).
https://www.youtube.com/watch?v=W_e5ZusMmxU
The one end of the platform, dumpster, or what ever has a set of 4” by 6” steel wheels this is normally the end that opens if there is a door. The other end has a large hook at the bottom. There is a set of steel box tubing that runs from end to end under the bottom.
The trailer or truck has a set of steel tubes that use 1 or 2 hydraulic cylinders to tilt to around 70*. You take a heavy winch line to the hook on the container. As you pull in the winch you can change the angle of the lifting bed. The tubing on the containers go on the outside of the tilting bed.
Are you able to set container on a dock or load a container that has sunken into the ground with that setup?
I also see people using the type I was talking about to haul sheds around They have smaller wheels on it and I think an air lift on the suspension.
I even have a frame that a 20' sea can sits on so I'm able to move it around. Great for job site office, work shop, and my portable electrical unit (genset with all our electrical control gear). Everything is bolted down and you have to do some clean up before hand or you'll have a huge mess. I'm sure I would not be road legal because of the height.