For example, to add a static route to the 10.0.0.0 network that uses a subnet mask of 255.0.0.0, a gateway of 192.168.0.1, and a cost metric of 2, you type the following at a command prompt:
route add 10.0.0.0 mask 255.0.0.0 192.168.0.1 metric 2
Source: https://technet.microsoft.com/en-us/library/cc757323(v=ws.10).aspx