|Normally we don't do peoples homework for them. And, I'm not going to now either. But I will point you in the right direction. That is, providing you've actually been paying attention in class.......|
the shop will have more than 20 computers for multiplayer gaming and 5 computers for personal or business use. the ssop will include printers, server, fax, photocopier.
So, you need to allow 25 computers and assorted printers, server, and fax machine to communicate with each other. There's a device that can allow this. Once you figure out what that device is, you'll also have your topology.
Since you will have also have some office computers, you'll want those separated from the gaming computers. There to keep them separate you'll want to use different subnets for the gaming and non-gaming computers. There's another device you'll need that can be used to allow separate subnets to communicate with each other. You'll need one of those as well as the other device.
Budget - you'll have to price all the equipment you'll require
wired or wireless? - which is more secure and provides better bandwidth? For gaming, you'll want all the bandwidth you can get.
network peripherals - You've already mentioned those above....HINT: a printer is a 'peripheral'
Security - I discussed securing your internal (business) network from the gaming network. I suspect you'll want internet access for the business LAN and likely the clients too. What device would provide me security from intrusion from the internet? I'll give you a hint......if you purchase the correct device, why, it can protect you from intrusion AND allow you to separate your gaming LAN from the work LAN.