Accessing LAN storage from Internet

I have a mixed network at home with a network hard drive, printer and a number of computers all attached through a modem router. I would like to be able to access the hard drive, and preferably the printer, from up at university.

I have solved the dynamic IP problem with no-ip but cannot work out how to connect to an internal IP address from outside of the network. All I know is that it will involve port forwarding which I don't understand in any detail.

Any one have any ideas?

Many Thanks
Matt