Cyber cafe network

I am working on a school project which requires me to come out with a recomendation for a simple office or company network. i need to show how the pcs, server and router are linked. to each other and the internet.
i have chosen a cybercafe with 20 client pcs + 1 administrator pc sharing one printer and scanner both positioned beside the administrator’s pc.

which topology should i use, how do, i link them all, and how should they be connected using routers, bridges, hubs or switches.

also what cabling is best and what softwares will i need.

the pcs are arranged thus:

5pcs on one row backing one wall of the room,
5pcs backing the other wall,
10 pcs on a middle row (5pcs placed back2back with 5 others).
Thanks