Chapter 6 Deploying Wireless Networks for FortiOS 5.0 : Wireless Mesh : Configuring a meshed WiFi network : Configuring the mesh branches or leaves
  
Configuring the mesh branches or leaves
The FortiAP units that will serve as branch/leaf nodes must be preconfigured.
1. Connect to the FortiAP unit web-based manager on its default Ethernet interface IP address, 192.168.1.2.
2. In the Connectivity section enter:
Uplink
Mesh
Mesh AP SSID
fortinet.mesh.<vdom-name>
For example, for the root domain, fortinet.mesh.root.
Mesh AP Password
Same as Mesh AP SSID.
Ethernet Bridge
Select
3. Select Apply and then select Logout.