Depends on your router. usually you just enable DHCP. Then tell it the starting address is 192.168.x.x and finishing address is 192.168.x.x and give a lease time and then maybe any exclusions you may want for something that's static.
To create a functional network with a switch you will need a DHCP server either from a router plugged into the switch or from an actual server that has DHCP installed on it. The function a switch brings to a network is to provide more ports for additional computers, when multiple machines are plugged into a network they need addresses in order to communicate. A DHCP server (from a router or traditional server) will provide an IP address to multiple machines thus assigning addresses that the computers can use to communicate on said network. A home router such as some made by Linksys or D-link should be sufficient to provide 12 computers with ip addresses. Just plug the router into the switch with the 12 computers and set the DHCP range for atleast 12 IP addresses.
router (config)# ip dhcp servicerouter (dhcp-config)# ip dhcp pool router (dhcp-config)# network
Just configure a DHCP server using router settings and you are good to go.
By using a router with DHCP turned on in the router
Check DHCP server settings, and also turn firewall off temperary.
They're probably set up to use DHCP to obtain an IP address from the router. It's likely you don't have a working connection to your router. Make sure your switch is connected to the router, and not just the other computers.
The ISR router acts as both a DHCP client and server.
Routers perform DHCP, which means the router acts as the "owner" of the network. If a router set it's own IP address to 192.168.1.1, then it will likely assign IPs to computers connected to it in the 192.168.1.x range. If you plug another router into your first router, the second router might have the IP 192.168.2.1, and then assign IPs in the 192.168.2.x range. This is what you want to avoid. Having all your computers on the same 192.168.x network is necessary. You essentially want to use your second router as a switch. To do this, disable DHCP in the routers admin UI. Then, instead of plugging the source cable (coming from your first router) in the "Uplink" port, plug it into one of the regular 1, 2, 3, 4 etc ports. This will enable your router to pass along IPs from your main router, rather than assign it's own. Plug other devices into 2, 3, 4, etc. You've essentially bridged your routers.
DHCP
Turn off dhcp in router settings.
router(config)#ip dhcp pool pool nameRouter(dhcp-config)# network x.x.x.x y.y.y.yx being the networky being the subnetOther settings are available for configuration.
integrated services router