I made this gif a while back. But it’s a good basic analogy. You load bitcoin into your node wallet and then open channels with one or more channel partners. A channel is a 2 of 2 multisig bitcoin address between you and your channel partner. As you send and receive payments the relative balance in those channels shift in and out. “The lightning network” is just a bunch of those nodes interconnected. The protocol routes payments by finding a pathway through interconnected nodes with a sufficient amount of liquidity to carry the payment through. If your node routes a payment then you pick up fees according to your channel fee policies.
