Here introduce the concepts of node and mining in CKB.
CKB is structured as a peer-to-peer network to run on top of the public Internet. The term "peer-to-peer" refers to all the computers that participate in the network, equal peers in the network topology. In this context, we refer each of these computers as a node.
All modern computers should have sufficient capability to run a CKB node and freely join the Nervos network.
Nodes in the network will synchronize existing blocks, transactions, and global state as well as receive new blocks and transactions from other nodes. Nodes will verify transactions, as well as broadcast new transactions to other nodes.
Miners are nodes that construct new blocks with a group of transactions.
In CKB, miners compete with each other to add blocks to the blockchain through Proof-of-Work. After a miner constructs a block, it will need to calculate the hash of the block (with a nonce) to produce a hash that is smaller than a specific target number (difficulty).
The miners who find a suitable hash will have the right to extend the blockchain by broadcasting their new blocks. Other nodes will receive newly mined blocks and verify them. Then miners will begin mining a new block on top of one of the new blocks they received.
The hash function for mining CKB mainnet is Eaglesong, you can learn more about it in [RFC 0010 - Eaglesong]: https://github.com/nervosnetwork/rfcs/blob/master/rfcs/0010-eaglesong/0010-eaglesong.md