HEX Lite VLAN with Ubiquiti Unifi

HI! I’ve just installed three Unifi APs and a RB Hex Lite. On the Unifi system i have 3 WLANs. I would like to create 3 VLANS on my RB, one only for the main WLAN, the second for the guest WLAN, and the third for the last WLAN, which should be used to connect PCs or Printers via Wi-Fi to the standard network used by the devices connected via ethernet. I have the RB far away from the room where there is the unmanaged switch and all the cables arriving from ports located behind the access point or things like that, the RB and the switch are connected by only one cable so i can’t use multiple ports but only one with the “standard network” and VLANs on it.
How can i do this project from the RB side?
Thanks for the help