Setting up Port Forwarding

Hello all, I am having an issue setting up port forwarding to set up remote access.

I am in my router settings but it is asking for some info that I cannot find on here or anywhere else.
Here is a screenshot with the port forwarding set up

I know the port and IP but I dont know what the external or internal are

External is the port you will using when accessing from outside and internal the port where YACReaderLibrary is running the server on. You can use the same port in both fields.