If you wish to configure the router to DDNS see below instructions:
1. Create an account in one of the router supported DDNS :
2. For example you can use https://now-dns.com/
3. After creating an account you will get your host name, user and password. (You should configure host name per router in case you wish to use multiple routers).
4. Select services menu --> Dynamic DNS and configure the account properties.
5. Check the enable.
6. If the service you selected is using https then check "Use HTTP Secure"
7. Under service select DDNS service provider you have selected
8. Under lookup host and host name enter the host name you got from the DDNS provider.
9. Enter your username and password you created the account in DDNS provider.
10. Click on save.
11. Now you should be able to access the router using host name instead of IP.