Explain symmetric encryption with session keys?

Unlike asymmetric encryption, in symmetric encryption the two parties in a conversation use the same key. After the TLS handshake, both sides use the same session keys for encryption. Once session keys are in use, the public and private keys are not used anymore. Session keys are temporary keys that are not used again once the session is terminated. A new, random set of session keys will be created for the next session.

Asymmetrical Encryption Symmetric Encryption