Hi, I'm very new and I don't understand a lot about networking further than port forwarding. I apologize for any mistakes. This is my learning experience.
I've looked and found a previous discussion that basically does what I want it to do. From my understanding, it creates two separate LANs, one with 192.168.11.0/24 and one with 192.168.22.0/24. The problem is that the solution uses an older version of OpenWRT and I don't understand how to follow it, especially given the VLAN section which doesn't exist in newer OpenWRT versions.
My requirements are slightly different and I want my topology to look something like this:
This is even easier than in the post you linked, since you have five independent ethernet ports, and you do not need to care about internal switches or VLANs. You can just define one to five network interfaces, each one with their parameters, then bridge the ethernet ports to the network interfaces.
Change the default lan interface under "interfaces" to use br-lan.1 (vlan 1)
Add another interface for the br-lan.2 with an ip address (or not) in your other subnet. (probably with since you probably what the openwrt to route between the two.
As @eduperez said, there is no need for VLANs here since the x86 ports are independently connected to the CPU and you are running only one network on each physical port.
What @clutch2sft said would also work. It is unnecessarily complicated at this stage but it does easily migrate to an advanced scenario with tagged VLANs on "trunk" Ethernet cables.