How to configure my Fortinet 524 switch to propagate Vlans to directly connect switches.

[jomfra]

Hello Support,

I have one Fortinet 524 D switch  on my network .

I also have (4) Fortinet 448 switches and (8) Fortinet 424D switches on my network.

I would like to connect all the 12 Switches (448 and 424D) to the 524D, effectively making the 524D switch behave line a backbone switch.

I  created 8 "Vlans" on the 524D backbone switch and would like these "vlans" to propagate seamlessly to the other switches.

It should be mention I do not have a FortiGate device in my network.

I Humbly request some guidance to achieve the above objective.

Thanks

Regards