NAS MyBook Single NIC + OpenVPN client firewall settings

Hello! I was able to successfully install and configure my MyBookLive (MBL) , I was able install OpenVPN with my configurations. This is where I have a problem, I want to route all the internet traffic through the VPN and allow all local IPs 192.168.x.x to have access to the MBL

I think my problem is with firewall rules but don't know how to configure properly, I think the single NIC port changes it from all the tuts online.

MyBook Live w/ OpenWRT
Single NIC (currently DHCP to main router or can change to static)
OpenVPN Client
VPN provider PIA

I can provide logs and more details but didnt want to flood the post.