How to set it up like this?
The OpenWRT router (TL-WR740N) is a wireless client.
The wireless network has a subnet of 192.168.0.x
The router has the address 192.168.2.1, because it is connected to the local network 192.168.2.x (DHCP is disabled, each has its own address statically registered: 192.168.2.101, 192.168.2.102 and so on)
It is necessary that access to the 192.168.0.x subnet (including the Internet) is available only to those who have either a VPN client or some other proxy client installed on their PC (192.168.2.101, 192.168.2.102, etc.)
Maybe someone has a similar ready-made configuration?
installed or running ? it's a big difference ....
There may be a language barrier (I know English at an elementary level)
VPN must be launched using standard Windows tools
You could block all access to 192.168.0.x in the 192.168.2.1's firewall, leaving only ports used by the
VPN and/or proxy to pass, going to the IP(s) of the proxy host and/or VPN server.
I need to first configure the router so that it connects the two networks.
then you probably should have opened with that ...
go to wireless -> scan -> join.
put the interface in the WAN zone.
btw, time to upgrade - https://openwrt.org/supported_devices/432_warning