How to create a WiFi Guest internet access on DAL routers.

Sometimes you need to provide internet access for your guests and visitors at the office or home.
Devices in the guest network are denied access to devices in the office/home network.
For this purpose you can create an additional WiFi network with its own security settings:

Please create a new Access point with a guest SSID that either requires or does not require a password:
Configuration >Network > WIFI > Access points > Add > "guest wifi"
Then create a new firewall zone:
Configuration >Firewall > Zones > Add > "guest wifi zone"
Then add the "guest wifi" into that zone 
Add a firewall rule allowing "guest wifi" zone to External zone 
Configuration >Firewall > Packet filtering > Add > "guest wifi rule"
That ia all.
Please don`t forget to remove a new Wifi interface from the Ethernet bridge.
Configuration >Bridges > LAN > Devices