[zeroxfe]

It's actually not that hard. Most blockchains use a variation of Gossip, which is quite trivial to implement. On startup, your nodes get a list of seed nodes, recursively ask for peer lists until they can connect to some "max peer count."

When they receive transactions (from a client, or a peer), they simply forward them to all other peers (if it's the first time they've seen them.)

That's basically it. :-)