I would personally recommend not using the WLAN wizard. To build a fully functional WLAN you need three things - a AAA profile, an SSID profile, and a containing profile known as a VAP or Virtual-AP profile. Each of these profiles have their own components, but for simplicity sake, let's say you need to do the following:
1. Create a new VLAN on the controller
2. Build the DHCP scope for that VLAN
3. Add that VLAN to a port
4. Build a AAA profile, can probably be the same as current guest
5. Build an SSID profile, this will be unique because the SSID will be different and hidden
6. Build a VAP profile, this will tie together the AAA, SSID, and define the VLAN.
7 Go into your AP group(s) and add the new VAP to the groups you want to broadcast it.
If you want to be extra cautious about effecting your other guest network, I would at least copy the existing guest AAA profile and rename it, in case you want to make changes in the future.
Does that make sense? If you Google Aruba Networks Profile Diagram, you should be able to find a diagram showing how all profiles are tied together.
For reference, you can also log into CLI and do a "show run" and grab each component of your current Guest network to better understand how they all tie together.
Michael Haring
If my answer is helpful, a Kudos is always appreciated!
