open port 88

I am trying to open port 88 on routeros 6.2. I am not sure what I am doing wrong. I wont attempt to post what I have tried as I have tried so many different things and I know the correct solution is very simple. Help here would be greatly appreciated!

create a dst nat nat rule destination ip as the in interface ip of the router dst port 88. Action dst nat to address of internal server port 88 specify tcp or udp. two rules if both. also known as port forwarding.