Need help with part two please most of all with Help with visual representation is where I am most lost

Part $2$: Practical Application but should also be able to communicate with each other.

Design a LAN: Draw or use a software tool to visualize your LAN design. Label key components.

IP Addressing: Decide on a private IP address range for your LAN. Assign IP addresses to each computer. Make sure the Sales and Engineering departments are on different subnets.

Security Considerations: What steps would you take to ensure the security of this network? List at least three measures.

Device Specifications: Choose a switch, a router, and other necessary components for this setup. Provide a brief rationale for each choice.