Hi all, 

I'm a complete networking noob and I thought I'd give it a try improving the networking of our business. 

This post was edited to better reflect what I am trying to do and what problems I encountered. 

I bought the following equipment:

ER5120 Router

T2600-28TS Main Switch
T1600-28TS Secondary Switch
OC200 WiFi Controller

2*EP245 

My goal is to setup 4 different VLANs with their own IP Pools and not be able to communicate with each other.

1. Admin (192.168.0.0/24)

2. Marketing (172.16.10.0/24)

3. Finance (172.16.20.0/24)

4. Personnel (172.16.30.0/24)

I followed this tutorial How to build up a multi-nets network via Multi-Nets NAT feature on TP-Link router with L2+/L3 switches? | TP-Link Brasil (tp-link.com) and it worked perfectly. I was able to create the different Wi-Fi SSID for each network as I liked. 

Problem is that they can communicate with each other by directly typing the IP of the server of another VLAN (as per the tutorial). 

I tried tweaking with the different steps from the tutorial, but I was not able to make the VLANs not communicate with each other. 

I was hoping someone might help me out in isolating the VLANs by possibly building on to this tutorial?

This network is live and hoping to find a solution before anyone finds out that they can access other sections :D

Thanks for the help!