Fortilink over P2P

I have two managed Fortiswitches that I need to connect over P2P.

I am following this KB:

https://docs.fortinet.com/document/fortiswitch/7.0.8/devices-managed-by-fortios/801183/fortilink-over-a-point-to-point-layer-2-network

I believe the KB details the steps needed for unmanaged Fortiswitches. I say this as the config switch physical-port does not work when I enter the CLI on a Fortigate.

Does anyone know the required to enable P2P on two managed Fortiswitches?

Thanks.