AirVPN setup on DDWRT not adding a tun interface

[Pankh 0]

I followed the instructions on their client site for DDWRT, which seemed to be a few UI versions behind but still accurate enough. At the point where I'm meant to add iptables, I checked my interfaces with ifconfig and there is no tun0 or tun1 interface. The VPN settings all seem correct, but it doesn't look like it connects at all

I tried rebooting the router but that didn't help. Are there any other steps I can check? The router is a RT-AC66U with DD WRT build 30709 or newer