Network Diagram

Hello im 27 years old, i need help with my homework and making a diagram of a business network

the design needs to have the following

• 50 employees - half Sales office and half Business office users
• 2 subnets - separate LANs within the office, 30 hosts per subnet (25 employees, 1 printer and 2 servers, and 2 more available addresses)
• 2 network printers - 1 per subnet
• 1 connection to the WAN/Internet
• 1 core router with 2 Ethernet interfaces (1 for each existing subnet) and 1 Serial for WAN
• Each subnet using 1 switch for all hosts
• Plan for growth for up to 6 subnets, which do not need to be in the diagram

I also need to create a subnet scheme which i found online
which is
LAN 1 192.168.4.0/24

LAN 2 192.168.3.0/24

i was wondering if someone could give me their input and explain to me the process, not in extreme detail just an explaination
this is what i have so far, please set me straight, this is kind of urgent

 

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