Port forwarding on a Planet router??

[nM3]

Hey.......
I have this Planet ADSL Router ADE-4100 and for some reason cannot get this port forwarding working on it. I have tried a few things and the manual that comes with the CD is pretty useless and does not explain a thing, except it says that it is possible but no explanation is given as how to do it...

Anyone with a similiar Router please could you help me on this little problem I am having

Thanks
nM3