Some OpenVPN Question

[Soloam]

Hello, I have a PfSense system that I'm using with "Private Internet Access" (PIA) VPN. I farly new to both pfsense and PIA, and I have some questions that I need some Help.

I have everything  working with PIA, but my torrent software (transmission) still marks my port as being closed. Without VPN all works well.

At the moment I have 3 interfaces, WAN, LAN and VPNPIA. And now my questions (sorry in advance if they are noob questions:

• I have the NAT forwarding set to my WAN interface, do I need do replicate it to my VPNPIA? (done this, still port closed).
• How does the pfsense handles VPN ports? The traffic arrives to my box on the VPN port, how does it passes the port to other apps?
• I read some posts that states that I need to handle the port forwarding in the PIA side, ok I get that, but the method sucks, no interface, is there a better VPN provider that allows me to manage this in a better way?

And now questions to make me understand better the pfsense package flow.

• When I receive a package from a VPN, do I need to add the rules to the WAN interface or to the VPNPIA interface?
• When I send a package from a VPN, do I need to add the rules to the LAN interface or to the VPNPIA interface?