Your question is TLS Handshake and Session Keys. Take a moment with it on the right.
Talk me through your thinking if you like. When you're confident, submit your answer and I'll grade it like a real screen (7/10 or better passes).
Describe the TLS handshake process and how it establishes a secure session key.
Explain the TLS 1.3 message flow, including ClientHello, ServerHello, certificate authentication, signature verification, and ephemeral key exchange. Contrast the key establishment and message flow with TLS 1.2 where relevant. Identify what an active network attacker can and cannot do at each stage.