Chapter 2 Advanced Routing for FortiOS 5.0 : Advanced Static Routing : Routing concepts : Adding a static route
  
Adding a static route
To add or edit a static route, go to Router > Static > Static Routes and select Create New.
Destination IP / Mask
Enter the destination IP address and netmask. A value of 0.0.0.0/0.0.0.0 is universal.
Device
Select the name of the interface which the static route will connect through.
Gateway
Enter the gateway IP address.
Distance
Enter the distance value, which will affect which routes are selected first by different protocols for route management or load balancing. The default is 10.
Priority
Enter the priority if desired, which will artificially weight the route during route selection. The higher the number, the less likely the route is to be selected over others. The default is 0.