These are quite clever. I'd love to have my own Borromean Box. That said, I've no clue how to start. It looks simple at first, but seems more complex the more

These are quite clever. I'd love to have my own Borromean Box. That said, I've no clue how to start. It looks simple at first, but seems more complex the more I think about it. Some construction details, videos, or other hints would be much appreciated.