Have a network and wifi question for totolink X5000R

sorry i'm new to openwrt

There are some questions that have bothered me for a long time, so I came up to ask you

My network environment is like the picture

I tried making wan&lan brige and tag vlan

But I found that my DHCP didn't work

And there seems to be an error in the x5000R WIFI setting on luci

Because I think I already have a FORTIGATE up front doing network security control

I just want my X5000R to do wired forwarding wireless and with VLAN on SSID

how do i set it up

Since my English is not very good, I use GOOGLE translation

Sorry for any grammatical errors

Why did you wish to do this - that's usually an invalid configuration.

???

You described any AP on the same VLAN as the 4 switch ports...maybe I missed something here?

Maybe my description is wrong

I was looking at how DSA 21.02 is configured

And my idea is that I want to put all the work on fireware

And my openwrt only needs to help me issue the SSID with vlan

Because it is the first time to play liunx's soft routing, I don't know how to set it up.

So how should I set it up?