Hello Roberto, the easiest way is to connect to your APs and enter the vSZ IP address : - In CLI : (login with username and password indicate on the stickers behind your AP) enter : "set scg ip your_sz_ip_address" then you can check the connection via "get scg"
- In HTTPS : (same login / password as above) go in "Administration > Management" Put "Set Controller Address (Reboot to take effect)" to enable. Enter the vSZ IP address in "Primary Controller Addr:" field. (same as CLI, you can ping the vSZ from "Administration > Diagnostics")
In both case, AP will reboot and you will find it in the "Staging Zone" of your vSZ.
If you have a lot of APs to do, it's better to redirect them via DHCP option 43. (your AP get autonatically vSZ IP when connecting)