How to Set NAT (Forwarding) and DDNS to Access CCTV

RouterOS General
1

Hi all Master Mikrotik, someone can help please..

In our office use Mikrotik RouterBoard (750G), and get IP Dynamic from our internet ISP.
and then we use DDNS from dlinkddns, because we have to connect to cctv from any place.

I set the IP for Mikrotik : 10.254.1.1 and Our Internet Modem : 10.254.1.2
CCTV IP : 10.254.1.100

So, How to config in RouterBoard using Winbox, setting NAT (Forwarding) and DDNS?
Does it need to use Script ?

Thanks before