At the bottom of that link there’s instructions on how to restrict access to the LAN from the SSID Guest:
Navigate to the Configure > Firewall & traffic shaping page.
- Ensure that the Guest network is selected on the SSID drop-down menu at the top of the page.
- In the Layer 3 firewall rules section, select Deny from the drop-down menu for the rule labeled Wireless clients accessing LAN.
Darren OConnor | doconnor@resalire.co.uk
https://www.linkedin.com/in/darrenoconnor/
I'm not an employee of Cisco/Meraki. My posts are based on Meraki best practice and what has worked for me in the field.