how to manage device group using cli

need to understand how to manage device group related policies using ssh to forti manager device.
like in device we can configure policy using 

Example: 
##config firewall policy
edit < Policy ID> 
set srcaddr < source IP> 
set dstaddr <destination IP> 
set service < <Service name>
set schedule <always or define schedule> 
next
end

same thing need to apply using FortiManager.