OpenVPN & LAN connectivity

Hi, I'm facing what seems to be a very common problem (I read at least 2 dozen posts all kind-of saying the same thing --- my OpenVPN is working just fine on the router, connection gets established, I'm able to traceroute/ping, etc but when I go to the LAN, I'm unable to reach the internet -- help !).

I, akin the others, also followed basic vpn setup link. Yet again the LAN doesn't work. Could it be that there is an endemic problem here and that maybe something is missing in the link/instructions noted ? From the link the part which I used (pasted-in) was part-1 "firewall". I'm not running a server, I have a service which I'm subscribed to meaning I'm simply a client. In passing, maybe something needs to be written to explain how to debug this better.

I've attempted so many things since encountering the problem (adding various uci directives, various iptable commands, etc) that I might have simply shot myself in the foot (yes, when you're not an expert in something you tend to paste-in anything you find that worked for someone else in lieu of trying to properly understand what the problem was/is). Is there a command I can run to reset the settings to their factory defaults (specifically on iptables, uci, route, etc ?) in order to start anew.

Finally, simplistically put - if I flash openwrt, install openvpn, upload my client ovpn file, get my openvpn working fine (ie. connection established) what else do I need to do to get the basic functionality to work from LAN (just that item-1 "firewall" from the link ? or anything else).

See my manual, if you have questions, ask: https://airvpn.org/forums/topic/20303-airvpn-configuration-on-openwrt-preventing-traffic-leakage-outside-tunnel/

To reset router setting completely see: https://openwrt.org/docs/guide-user/troubleshooting/failsafe_and_factory_reset#soft_factory_reset

@vgaetera Error in the instructions, or error on user side? Can you please comment?

There is firstboot which is like reset to factory defaults.
There is nothing for individual components.
However you could copy the configuration files from the rom. For example:
cp /rom/etc/config/dhcp /etc/config/

Yes, and it is quite important otherwise NAT will not work on the VPN connection.

Hard to say if we don't see configs and traces. This goes to you too @tfft !