The block creation process in PoET involves the following steps:

1. *Block assembly*: The selected validator collects and verifies a set of unconfirmed transactions from the mempool.

2. *Block header creation*: The validator creates a block header, which includes:

- Block number

- Previous block hash

- Timestamp

- Transaction hashes

- Validator's public key

3. *Block hash calculation*: The validator calculates the block hash using a cryptographic hash function (e.g., SHA-256).

4. *Block signature*: The validator signs the block using their private key, ensuring the block's integrity and authenticity.

5. *Block broadcast*: The validator broadcasts the new block to the network, where it is verified and added to the blockchain by other nodes.

6. *Blockchain update*: Each node updates its local copy of the blockchain by adding the new block, ensuring a consistent and up-to-date ledger.

By adding a new block to the blockchain, the selected validator has successfully extended the chain, allowing the network to build upon the newly added transactions.