1. You should be fine with documenting the requirements. They seem pretty staright forward in your scenario. You might want to check with your teacher if it's a requirement to allow for expansion ie another LAN or more nodes attached.
2/3. In my above post, I'm assuming that's the type of network structure they want. I was also trying to put it into a more realistic situation. You'll definitely need a server room. This is where you'll have your racks for all your server types and related hardware.
Racks: Will house your servers and networking equipment. They will also have cooling systems in place.
Servers: File, Mail, Proxy, Intranet, SAN, Backup, UPS.
Networking: Router, Switches, Patch Panel, cables.
*Things you may need to add which may be out of scope
A) security to the server room; (B) how the phone lines? / MDF? - very often in companies of that size, the IT will manage the phone lines and PABX.
4. TCP/IP
why would you use anything else
You can write up about VLANs, DHCP in this part.
5. Make sure you cover every aspect. include diagrams, etc. And maybe even do some light research on what hardware you'd recommend.
topology - star will be fine. everyone uses star.
**if you don't understand any of these terms. do a bit of light reading. it'll help you.
and if you still do'nt understand, feel free to reply
***forgot about printers... i'm assuming it is a printing company.... so you might want to chuck in Print Server too!