[Solved] How to setup separate two (2) LANs networks on OpenWrt 18.06.5

[habagat]

Hi Trendy,
Many thanks for your support! and it's really an easy task. For the benefits of the readers here are the simple detailed steps I have made.

Login to Luci web interface.

A. Create New VLAN3.

1. Click Network --> Switch then click "Add" button to create new vlan3 as shown in the picture ports 3 and 4 are untagged and CPU is tagged.
2. Click the "Save and Apply" button.
   
   

B. Create a new Interface (lan2).

1. Click Network --> Interfaces Click "Add new interface" button.
   Set the "Name of new interface:" to lan2
   Set the "Cover the following interface" to eth0.3
   Leave the "Protocol of the new interface" to its default setting "Static address" the click the "submit" button.
2. LAN2 will be created as a new interface click the edit button.
   Set the following fields.
   IPv4 Address: 192.168.22.1
   IPv4 netmask: 255.255.255.0
   IPv4 gateway: 192.168.22.1
   Use custom DNS servers: Leave this blank
   Note: Please Do not use DNS server unreachable from lan2 interface.
   
   

C. Create a new Firewall zone.

1. Click Network --> Firewall click "Add" button under Zones.
2. Set the following in the "General Settings" Tab.
   Name: lan2
   Input: Accept
   Output: Accept
   Forward: Accept
   Covered Networks: select "lan2"

Inter-Zone Forwarding
Allow forward to destination zone: select "wan wan6"

3. Click "Apply & Save" button.
   
   

That's it and you are done!

Again thank you so much!