NAS WAN connection : New Router/ Modem the issue?

[Nigel A]

Hey folks,  I'm pretty new to Networking so hopefully this isn't too stupid a question. I have a NAS LS210D that works great within my LAN, (access via PC , mobile, tablet all fine). However, I cant access the NAS from outside the LAN. Background, I recently changed ISP and went Fiber Optic with a local provider. Great speed and no issues with service, but the new ISP replaced my old modem with a new modem/ router combo. The new modem/ router has the wifi disabled but is set up as a 'router' and not as a bridge. So my question, how do I make my NAS visable to WAN connections ? Really not sure where to start ..... NAS config or Modem/ Router set up ?  Any help much appreciated.  Cheers.
Modem/Router     Zyxel  VMG4381
Router  Netgear    R6700   

[Texturtle]

The NAS really isn't designed for general access from the WAN, but you can configure it for limited access.

http://www.buffalotech.com/knowledge-base/setting-up-webaccess-on-a-buffalo-linkstation

[diegovz01]

I have the same problem