Binding Port to Server

I did everything the guy told me to do
port-forwarding-without-access-router-t5164.html

I made sure i have everything done ....but when he said to bind the port i thought that was to put the ipv4 in the server ip thing in server.properties.....i did that and i wanted my friend to come on but he cant....any help plz .......i had my brother try and get onto the server and he can but i think thats because we share the same router