Dynamic DNS (DDNS): go to Advanced > DDNS > Add. Select your provider (noip.com, dyndns.org, etc.), enter your domain name, WAN interface, and account credentials. Combine with Port Forwarding to reach specific services.
Remote Web UI management: go to Security > WAN Access. Select the WAN interface, set a port (default: 8080), check Enable, and click Save & Apply.
Warning: Remote Web UI access exposes the administration interface to the Internet. Use a strong password and only enable this when strictly necessary.