OpenVPN with OpenWRT question

Hi everyone!
I don't know what is the problem with my configuration.
I have router Mikrotik RB951Ui-2Hnd with OpenWRT,
I connected with Ethernet cable my computer with router, so I have LAN (
Also I have modem Huawei e3372, and I connected it to usb port on my router.
I've installed packages usb-modeswitch, kmod-usb-net-cdc-ether, created interface called "MODEM" as DHCP client, so it takes ip address from MODEM and there are another network (
Created Firewall rules to forward from LAN to MODEM.
Now I have internet access on my computer.
After that I bought VPS and created there OpenVPN server with that script:

Installed packages openvpn-openssl, luci-app-openvpn.
Created interface called "VPN" with unmanaged protocol, uploaded .ovpn config inside LUCI, started that OpenVPN service. Now my router can access to internet with the VPN (I checked it from terminal), but my computer doesn't have that access. The only thing that I can do is ping and access my VPS. Can you please help me to realize what is the problem? I think I should choose another script, because that one doesn't know what to do with traffic from my networks.