the NAS will be using your router's WAN IP (assigned by your ISP) but you need to do the port forwarding to have access to the drive over the internet
I know how to forward ports but would I just need to forward just a single TCP/UDP port to my NAS's IP? and how exactly would you enter that when mapping? like this for eaxample?... \\example.dyndns-office.com\10.0.0.50:8888?