Read the research paper about the Chord algorithm: https://pdos.csail.mit.edu/papers/chord:sigcomm01/chord_sigc..., then implement the algorithm on your own (paper contains pseudo code).

Or start here, generally read high level details about the algorithm: https://en.wikipedia.org/wiki/Chord_(peer-to-peer).

The most widely used DHT is Kademlia from Petar Maymounkov and David Mazières. It is used in Ethereum, IPFS, I2P, Gnutella DHT, and many other applications.

https://en.wikipedia.org/wiki/Kademlia

https://pdos.csail.mit.edu/~petar/papers/maymounkov-kademlia...

https://web.archive.org/web/20120128120732/http://www.cs.ric...

If you scroll to the bottom, I've a linkdump worth considering: https://h0p3.nekoweb.org/#Outopos%3A%20DHT

Here is an description for the BitTorrent DHT

https://stackoverflow.com/questions/1332107/dht-in-torrents#...

https://blog.anacrolix.link/posts/how-not-to-implement-a-dht...

Also understand how they can be used for unique hard to detect "Scams" like MaidSafe. "We came up with a brand new amazing way to dht! like ants!"

This all sounded technically interesting and useful, and only after ingesting huge amounts of all the technical details do you realize the whole plan was to force everyone to re-write all internet applications over again (dumb) and then it evolved into some slow scam where after 10 years or something they pretend its still being worked on, but nothing ever finishes.