Just plug in one switch into the router and the other switch plug into the switch that's pluged into the router.
For patch panels, you can have a 2 patch panels before each switch that connects the computers & printers to and from a patch panel to another patch panel to the switch. Make sure to label the incoming & outgoing cables, not the small cables that connect the patch panels to each other and the patch panels.
NOTE: Normally patch panels are used in medium to large scale business to keep organized and disconnect ports if no one is suppose to use them if not occupied.
For the server, put it on the switch that's connected to the router directly or another port on the router and assign the server an static ip.
The server (assuming windows server & depending on what version) can be used to manage all 20 pcs and 4 printers with Active Directory, WSUS, Printer Services, etc.
Pretty much, a server will be central point of management of the entire network depending on what jobs it will be assigned.
Plus the server with active directory would be less of a hassle than peer to peer networking.
Edited by Nate15329, 18 April 2011 - 11:58 AM.