You need to do a couple of things to create a guest network.

• Click on Network → network configuration
• Click on the plus symbol next to guest configuration
• Now you need to select a LAN port a WAN port and a Mode (managed or unmanaged)
• Fill in a ip address, subnet and enable NAT
• Click on the save button and if ask apply configuration

Next step is to configure the DHCP

• Click on network → DHCP
• Click on the plus symbol
• Select the correct interface and the other values will be filled in automatically.
• Click on the save button and if ask apply configuration

To reload the network:

• Click on the twisted arrows in the upper right corner