After you check that out, post back if you have any questions. Basically, you will create 2 virtual interfaces; i.e. interface vlan 10 and interface vlan 20 then assign ip addresses to each interface. Next you enable and configure one of the routing protocols; i.e. RIP, EIGRP, or configure static routes to each subnet with the gateway being the ip address of the virtual interface for that subnet.
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Cisco Catalyst 3750