You can only implement VLANs on at least layer 2 switches. Layer 3 switches are like fast routers, that’s about as basic as I could describe it. Layer 2 however is a switch based on MAC addresses and bridging. Layer 2 switches learn MAC addresses automatically. This builds a chart or table of addresses and ports and associated network devices. This chart helps the switch selectively send data, instead of trying each port for availability. The reason this applies to VLANs is because u can stick a VLAN on a port assignment, and the layer 2 switch will always point to that port for the MAC addresses of the device or devices on the VLAN.
Hope this helps!