@dws520 

Depends on what you want to do.

For example to get to a security Cameras NVR, using port forwarding is common way to do it and Virtual Servers option in the router for server access. Some routers have a "remote access" option.

See the user guide for instructions as it may vary with different routers. 

Basicly you need your IP address for your network (use "what is my IP" to see what it is) and use that to get to your network. If it is dynamic IP or to help make it more secure, you may want to set up a DDNS also easier to remember.