How to restrict access between WAN and LAN?

[lokus]

Hi there all. I don't know how to configure the router for my needs. Situation is like this:

ISP Modem/Router/AP 192.168.0.1 which takes all my cable/Wifi devices than cable RJ45 goes into WAN of Tp-Link WR-741ND V1.1 (Gargoyle 1.1). This Tp-Link I want to use for wifi connectin to Smart Sockets / Smart Bulbs and other Smart Cloud devices and I don't trust those devices so I want them sit in restricted separated wifi on separate router/ap.

Tp-link 192.168.100.254 can ping to 192.168.0.15 - pc connected through RJ45 with ISP main router. But I don't want tp-link and all devices connected to it to get access to other computers from 192.168.0.x. How to do it?

[Lantis]

Can you please confirm what version you're running?
Is it really "Gargoyle 1.1"? If so, why such an old version.

You can use the Firewall -> Restrictions page and block the 192.168.0.1/24 subnet.
Note that you might need to allow the upstream router specifically for DHCP/DNS etc.